In a career spanning thirty years, Dick produced thirty-five science fiction novels and more than a hundred short stories. Quite apart from his prolific output of SF, he wrote a dozen mainstream novels, only one of which sold in his lifetime. He was writing SF during a period when the genre was undergoing a slow but profound transformation. In America in the fifties, science fiction had still to throw off its lowly pulp origins (in Britain and Europe, SF could boast a loftier lineage, citing Wells, Huxley, Stapledon and Verne as its forebears). US magazines were full of badly-written space adventures featuring mad scientists and ravaging alien monsters, clumsy stories of futuristic technology with little concern for the finer points of style or characterisation. Titles such as Super-Science Fiction and Thrilling Wonder Stories paid a cent a word to hacks cashing in on the pulp SF boom (in 1953 there were more than thirty genre magazines published every month). There was, however, a core of talented writers with an unshakeable belief in the visionary function of the SF field: the fifties and early sixties saw the emergence of authors who would bring an increased literary sophistication, an appreciation of psychological depth, and a heightened social awareness to the genre. Dick was one of the very best of these writers - but eventual recognition was to prove hard-won and long delayed.

Philip Kindred Dick, born in Chicago in 1928, was a maverick, a self-taught anti-establishment intellectual with an appetite for knowledge and an intimidating ability to absorb information. He had a thorough grounding in philosophy, psychology and religion. He was studying Jung before he was fashionable, along with the thinkers of the German Enlightenment, Gnosticism, and Eastern religions; and he had, also, a thorough knowledge and love of science fiction. In the Berkeley Beat milieu of which he was a part in the forties and fifties - he briefly attended University of California at Berkeley, majoring in philosophy, before dropping out without graduating - Dick combined writing mainstream novels and science fiction, often suffering the ridicule of acquaintances for the latter pursuit. He published his first science fiction short story in 1952, and wrote eight SF novels, around a dozen mainstream novels, and over eighty SF stories in the fifties. He typed 120 words a minute and claimed that he plotted as he wrote.

Dick's mainstream novels failed to find a publisher, a state of affairs that grieved the young writer who craved recognition from his intellectual peers. His early short stories sold to a variety of genre magazines, and his SF novels were published by Ace Double paperbacks with two short novels in a single volume, each one upside-down in relation to the other. These books boasted not one lurid cover but two, featuring the standard fare of rocket-ships, aliens, and space-suited heroes.

At first glance, Dick's early novels conformed to type: he used the popular leitmotifs of SF - alien worlds, precognition, ray-guns - but employed them to his own agenda. While much SF of the time extrapolated from the hard sciences, Dick used SF to explore his obsession with metaphysics, the nature of perceived reality, good and evil, and the abuse of power. He was obsessed with the idea that the universe was only apparently real, an illusion behind which the truth might dwell. Again and again in his work, we find that reality as perceived by both reader and protagonist is a hoax, a shadow play conceived by malign forces. Later novels such as Martian Time-Slip (1964), Ubik (1969), and Valis (1981) explore this theme exhaustively. Another of his concerns was what constitutes a true human being, as opposed to a fake - a question he explored in the novel Do Androids Dream of Electric Sheep? (1968), among others.

While investigating such major themes, Dick was populating his novels with a repertoire of fully-realised characters drawn from real life, composites of people he knew and versions of himself. He wrote about big ideas in his fiction, but never lost sight of the fact that science fiction was about the effect of events on individuals. One of the many strengths of his work is the empathy with which he wrote about ordinary people in extraordinary circumstances.

There can be few writers, especially within the SF field, who drew so readily upon the events of their own lives. To a great degree, his art reflected his life - and it was an eventful, troubled and chaotic life.

Dick and his mother moved from Chicago to California when he was four years old and he was to live there (except for three years in Washington D.C. from the age of six) for the rest of his life. His family relationships were difficult. Dick believed that his mother had neglected his twin sister, a girl named Jane who had died five weeks after her birth. He was deeply affected by his twin's absence and blamed his mother for her death. His father had deserted the family when Dick was four - this was another major factor in his complex and troubled psychological make-up. Throughout his life he suffered anxiety attacks and periods of being unable to function socially; he was agoraphobic and had difficulty eating in public. During the sixties, following the failure of his third marriage, he became dependent on amphetamines and prescription drugs. He was paranoid (convinced at times that he was being watched by the FBI and CIA), and was crippled by frequent bouts of debilitating depression which culminated, on more than one occasion, in attempts to take his own life.

And yet, during the course of five failed marriages, psychiatric therapy and drug dependency, he continued to write some of the most strikingly original science fiction novels of the sixties and seventies.

In 1961, after a two year period in which he wrote three mainstream novels (which failed to sell) Dick returned to science fiction with what many critics regard as his finest novel, The Man in the High Castle.

Less frenzied in tone than much of his SF both before and after, and less surreal, the novel employs the realistic voice of his then unpublished mainstream novels. Set in contemporary America (circa 1962), The Man in the High Castle has none of the trappings of his SF to that point: no air-cars or rocket-ships, talking gadgets or telepaths. Compared to his earlier SF, it is measured and sophisticated. It was Dick's first novel to be accepted by a literary publisher, Putnam's, and received the Hugo award for the best SF novel of 1962.

In the novel, the Axis powers have won the Second World War. America is divided into three states, the eastern third ruled by Germany, an autonomous central Rocky Mountain State which acts as a demilitarised buffer zone, and the Pacific Seaboard America, governed by the Japanese.
The world is divided between these two super-powers, with Japan governing Asia and Germany ruling Europe and Africa. Dick portrays Japanese rule as comparatively benign: Nazi Germany is the true evil. Early in the novel we learn, in a chilling aside, that Germany has already applied the final solution to the inhabitants of Africa. Hitler is insane, and incarcerated in a psychiatric institution somewhere in the homeland. The health of the Chancellor, Martin Bormann, is failing as the novel opens and a power struggle between hard-line Nazis including Göring, Goebbels, and Heydrich, is under way. The political in-fighting is for the most part played out in the wings, leaving the stage free for the common men and women that Dick - unlike many science fiction writers of the time - relied on again and again in his novels and stories.

The evil of the Nazi regime is only ever referred to in the early narrative, never overtly presented. Instead, Dick is more subtle in his depiction of the effect of totalitarianism on the average citizen. In chapter 1, Frank Frink considers leaving the Japanese-governed western states; he rules out the Rocky Mountain States, and then: "What about the South? His body recoiled. Ugh. Not that. As a white man he would have plenty of place, in fact more than he had here in P.S.A. But... he did not want that kind of place."

In chapter 3, Baynes, flying to San Francisco from Europe, falls into conversation with a young German artist named Lotze, and through the artist's anti-Semitism and casual assumption of cultural superiority we are granted an insight into the insidious nature of bigotry. Likewise we observe, in the character of small-time entrepreneur Robert Childan, who sells fake antiques to Japanese fascinated with Americana, an admiration of the Nazi cause. In chapter 2: "After all, they had barely managed to win the war, [...] while at home they had passed edicts which... well, at least the idea was good. And after all, they had been successful with the Jews and Gypsies and bible students. And the Slavs had been rolled back two thousand years' worth, to their heartland in Asia. Out of Europe entirely, to everyone's relief." In a wonderfully ironic touch, Dick has Childan's speech patterns and interior dialogue unconsciously imitating those of the Japanese he both despises and admires.

Later in the novel, increasingly, we come to understand the extent of the Nazi evil. Again, though, Dick refrains from crudely showing us, via direct action, the terror of Nazi rule. Instead, more subtly, he presents the horror of the regime through the musings and reflections of his characters. The expert use of interior monologue, a technique Dick employs again and again in his novels, allows the reader to inhabit the psyches of individuals driven to contemplate their powerlessness in light of the ultimate rule of the Third Reich.

And yet, as Dick shows us, it is a situation not without hope.

The Japanese occupation of the Western states has brought about the use of the I Ching, the ancient Chinese book of divination. In opposition to Nazi ideology, Dick posits the philosophy of Tao, which offers a means of examining the universe through the principals of inter-connectedness - or Jungian synchronicity - at odds with Western ideas of a universe that functions on the mechanistic basis of cause and effect. In his use of Tao, Dick suggests that the world presented in The Man in the High Castle is but an illusion, that other, better worlds might exist.

The novel's two main characters consult the I Ching. Juliana Frink works as a Judo instructor in Colorado in the Rocky Mountain buffer state. She is in limbo after separating from Frank, her husband. She meets Joe Cinnadella in a diner and finds herself attracted despite herself to the fascist war hero. In many ways Juliana is the novel's most passive character; she consults the I Ching less through a spiritual motivation than a need of direction - and yet through Juliana and her actions we are offered a glimpse of the truth that is the crux of the novel. In the portrayal of her uncertainty, her dependence and indecision, Dick achieves one of his most sympathetic and fully-realised characters. Chapter 13, describing her arrival in Denver with Cinnadella, her growing fear as she discerns his true intentions, maintains a suspense which culminates in an horrific, though underplayed, confrontation between the two. Thus freed, she is able to continue to her rendezvous with the Man in the High Castle.

Nobusuke Tagomi, the head of the Japanese Imperial Trade Mission in San Francisco, is presented as the book's spiritual heart, an embodiment of the wisdom and humanity of Tao. Used as the middle-man in a meeting between German agent Baynes and a high-up representative of his own government, Tagomi comes to face a dilemma in which even the ruling force of his life, the I Ching, cannot aid him.

The novel builds slowly, following the fortunes of Tagomi, Juliana, agent Baynes, and Frank Frink, Juliana's estranged husband, who is sacked from his job manufacturing fake American artefacts and begins his own business creating original jewellery. They are, with the exception of agent Baynes, regular, small-time citizens whose actions within the framework of the story will effect the lives of each other. They are, like everything in life - as the philosophy of Tao makes clear - inter-connected.

The terror of implicit evil, the claustrophobic sense of being imprisoned in a world seemingly without hope, accretes inexorably. Individuals, with whom for the most part we have come to empathise, find themselves trapped in circumstances beyond their control. Dick has set the stage in a sub-genre of science fiction little explored at the time he wrote the novel, that of the Alternative World. What if the allies had lost the war? How might the march of titanic circumstance effect the ordinary citizen? In Dick's hands, however, it is a what if scenario with a twist.

The Grasshopper Lies Heavy is the novel within the novel, a work of science fiction by Hawthorn Abendsen detailing an alternative world in which the allies won the Second World War. The book is banned by the Japanese and German authorities, but openly on sale in the Rocky Mountain States, where Abendsen resides - supposedly in the fortified High Castle of the title.

Juliana Frink becomes obsessed with the vision of this other, better world. Other characters refer to Grasshopper throughout the novel: the reader gains the gradual impression that Abendsen, absent until the very last chapter, is in some way a visionary whose insight might prove revelatory. However, the meeting between Juliana Frink and Hawthorn Abendsen in the last chapter is at once a disappointment for Juliana, and at the same time a moment of conceptual breakthrough. She makes a discovery that changes her perception of reality - always a dominant theme in Dick's work - as she learns how Grasshopper came to be written.

There are no neat resolutions in The Man in the High Castle. In all his fiction, as in his philosophical investigations, Dick abhorred the easy answer. Just as we cannot be sure of the fate of individual characters, we are left wondering at the fate of the world. As with all great literature, The Man in the High Castle grants us an insight into the minds of real, fully-developed characters moulded by circumstance; like all great SF, it gives us a what if glimpse of another world, a reality we are invited to compare with our own.

Philip K. Dick died in March 1982, at the age of fifty-three.

The same year saw the release of the film Blade Runner, based on his novel Do Android Dream of Electric Sheep? The film spurred world-wide interest in his work, leading to the re-publication of his science fiction titles and the publication of his mainstream novels. Under-appreciated during his lifetime, the works of Philip K. Dick have at last achieved both the academic and popular attention they deserve.

The Man in the High Castle, in its depiction of little people living small lives with honour and confusion - and in its examination of the conflicting ideas of totalitarianism and Eastern philosophy - is perhaps Dick's finest book, and one of the very best science fiction novels ever published.

• Martian Time-Slip, Philip K. Dick.
• The Three Stigmata of Palmer Eldritch, Philip K. Dick.
• Do Androids Dream of Electric Sheep, Philip K. Dick.
• Flow My Tears, the Policeman Said, Philip K. Dick.
• A Scanner Darkly, Philip K. Dick.
• Philip K. Dick, Andrew M. Butler, Pocket Essentials, 2000.
• To the High Castle, Philip K. Dick: A Life, Greg Rickman, The Valentine Press, 1989
• Mind in Motion: The Fiction of Philip K. Dick, Patricia S. Warrick, Southern Illinois University Press, 1987.
• Only Apparently Real, Paul Williams, Arbor House, 1986.