"I think that landscape is a formalization of space and time, and the external landscape directly reflects interior states of mind – in fact the only external landscapes that have any meaning are those which are reflected in the Central Nervous System, if you like, by their direct analogues." – J.G. Ballard

The first question that arises, and undoubtedly the most problematical, is to identify what is meant by a "science fiction" film. This book provides a whole range of answers, more by implication than definition, and the range is indicative of a positive indecision rather than a wish to encompass all preferences. Science Fiction is after all a vast subject, rendered only more complex when translated into film.

H. G. Wells (1886-1946), whose influence lurks surprisingly behind much that is in this book, called his own writings "fantasias of possibility", an expression all the more pleasing for its relevance to any kind of fiction. The Polish writer Stanislaw Lem, however, has suggested that the only way to progress is by abolishing formerly valid definitions, and since science fiction is concerned with progress there is little sense in expecting it to conform to a fixed pattern. The only constant thing about it is that it changes all the time.

This collection of essays examines the identity of science fiction cinema. At the core is a narrative that argues that in principle the cinema "is" science fiction. It deals with unrealities in a mood of total conviction. It demonstrates alternatives and allows you to share in them. It is a fantasy constructed around actuality, and the translation of ideas into images. Any film worth experiencing is one that hauls you in for ninety plus minutes, finally to disgorge you in a state of dazed rebirth, and the same applies, of course, to the science fiction genre.

The paradox of the science fiction film is that it carries its own contradictions within itself. A fully functional space station, may not be orbiting the Earth right now, but "2001: A Space Odyssey" has actually shown us the thing in full flight, and with far greater clarity than any NASA transmissions have been able to achieve. The space station has "already" been filmed; after Kubrick, you might say, there seems little point on producing the genuine article. If you want to know what it’s like in space, the whole experience is made safe and easy for us by "2001", preferably in widescreen. Isaac Asimov (1920-1992) said that he had come to live in the world that he had written about in the 1950s, and much of his fictional technology has come true. What was once speculation has gradually turned into the contemporary landscape.

"Liquid Metal" brings together a number of seminal essays that have opened up the study of science fiction with serious critical interrogation. It begins with an exploration of the generic specificities of its form, and concludes with a historically specific case study with 1950s invasion films. It is divided into eight distinct, themed sections including, the cyborg in science fiction; the science fiction city; time travel and the primal scene; the disaster imagination; science fiction fandom; and 1950s invasion narratives and includes important writings by Susan Sontag, Vivian Sobchack, Steve Neale, J. P. Telotte, Peter Biskind and Constance Penley, covering such films as "Bladerunner", "Alien", "Star Wars", "The Terminator", "Total Recall", "Invasion of the Body Snatchers", "Them!" and "The Thing!".

The book succeeds as an illuminating study of the science fiction film, as well as a work of pointed literary and cultural criticism, revealing how this genre has captured the popular imagination while transforming the physical and social world in which we live.

"The exploration of the unexplorable" is perhaps the most acceptable definition of the science fiction film, wide enough to include the broad range between the "Wonder of Science Fiction" of the first chapter to the "Look to the Skies!" of the last. In the cinema of the fantastic, the speculative and the surreal, the filmmaker satisfies not only the basic requirement of entertainment by striving to provide new and fresh experiences, but also the human mind’s healthy refusal to withdraw from its deepest hopes, fears and dreams.

The most voracious human appetite is the imagination – an innate hunger for exploration, knowledge, and ever-greater miracles. The science fiction film, stemming from the imagination, stimulates it further. Such is its unique value – and its unique excitement.