Let me begin by going out on a limb and stating quite boldly that I think Mamoru Oshii is one of the most significant individual figures working in Japanese cinema today. With the industry becoming increasingly defined by vapid, commercial "idol" movies destined for the domestic market, which, with their glossy production values matched only by the slackness of their scripts, are of little interest to anyone outside of the country's pop-culture frame of reference, it is almost ironic that one of the most thought-provoking and introspective movies of the year, Ghost in the Shell: Innocence, was made in a medium traditionally looked down on by most mainstream viewers: animation.

Oshii is no typical anime director and it would be a big mistake to assume his works in this labour-intensive and high-risk commercial industry typify the genre. They aspire to so much more than the competition, both in terms of their content and their technical accomplishment. As Oshii himself frames it, he seems himself very much an outsider within the industry, often referring to himself as "a stray dog". Pushing the cyberpunk genre to its very limits and beyond, Oshii doesn't make films for a predetermined demographic. Rather, he is a director who, over the past two decades, has more or less created his own audience, and an international one at that. And not just in animation either. Let us not forget that he has brought his own highly individual vision into the live-action realm too, for example by utilising new computer technologies to investigate the levels between constructed and consumed reality in his previous movie, Avalon (2000).

It is no bold claim to say that Oshii proves a challenging director for most audiences. As the reception of Innocence at this year's Cannes Film Festival suggests, his recent work requires such a degree of engagement that those in search of conventional plot mechanics, unambiguous characterisation and sense of being confronted in a world readily recognisable to themselves are advised to search elsewhere. The common consensus at Cannes saw most critics marvelling at Innocence's images but left outside its cold, dramatic core.

Such reservations are understandable. One gets out of an Oshii film what one invests into it. The director makes little attempt to leave his films open to any form of explanation. By creating lavishly detailed worlds that remain open-ended enough for the individual viewer to grope around in, for those willing to immerse themselves in his oeuvre, the benefits are obvious. Throughout his career, Oshii has left a trail of crumbs of ideas, and left it up to the viewer to find out where he is going. Though one often begins to wonder if he knows himself, we do get to follow his train of thought, and shudder at the implications of where it is taking us.

Bridging the gap between thorough scholarly analysis and clear, accessible writing for the general reader, Brian Ruh's timely book is a welcome study of a director whose works openly invite closer analysis. Taking a chapter-by-chapter look at Oshii's individual works, beginning with his contribution to the animated TV series Urusei Yatsura (1981-84) through Angel's Egg (1985), a thematic turning point that had some anime fans howling in frustration, he traces the themes and intellectual concerns throughout his body of work leading up to, but not including this latest film. Ruh charts the increasing centrality of such recurrent motifs as the aestheticisation of technology (especially military), the usage of mythological and religious symbolism and allegory as they become further detached from their origins, and the questions of identity and reality in a rapidly changing society - "how technology alters how one perceives the world".

A lot of Western writing on Japanese animation has a frustrating tendency to get bogged down in the details of that tricky area of "cultural specificity" whilst missing the more interesting broader picture. Is Japanese animation really intrinsically different from the animation of other countries, and if so, why this might be? Attempts to explain away differences in the style or content of anime as if it were part of a closed system unrelated to other cultures, or indeed, other media forms, has resulted in a lot of unsatisfactory writing on the subject, and anime writers who take this approach easily lay themselves open to accusations of fetishising Japan, not to mention drawing the appreciation of the anime genre into a closed-off otaku ghetto.

Ruh opens his analysis of Oshii's best known film Ghost in the Shell in chapter six by citing Japanese sociologist and media critic Toshiya Ueno, who in the past has been highly critical of Western fan appreciation of animation. In the quote Ueno draws attention to the implicit assumption of one author that "anime is more interesting for 'western' people than for the Japanese because of its cultural specificity" - that it can thus be used as an avenue to learn about "Japan" from afar.

Thankfully, for the most part, Ruh avoids such pitfalls. His observations are relevant to the films at hand, not trite generalisations. This is, after all, an auteur-based book, with the point of reference between the films being the director rather than the country in which they were produced. Obviously many of Oshii's own political views were shaped by the events occurring in his own country as he was growing up - for example, in the struggles of the Japanese student protest against the renewing of the Anpo security pact in the 1960s, which allowed America to keep their troops on Japanese soil, and the Japanese government's subsequent collusion in the Vietnam war. This is all valuable background information that has considerable bearing on allusions in Oshii's films to the US presence at the Yokota Airbase, which "serves as a weak point in Japan's landscape, permeable to dangerous imperial imports" - a possible gateway through which nuclear weapons are smuggled in Patlabor 2, and a haven for the vampires to congregate around in Blood the Last Vampire (which Oshii did not direct, but in his capacity as a Supervising Producer, most surely had some input on), as Whitby was in Bram Stoker's original novel of Dracula.

But there is little specifically Japanese about a director who cites such eclectic visual influences as the Russian live-action director Andrei Tarkovsky or the German surrealist artist Hans Bellmer, and who is as likely to cross-reference Arthurian legend (in Avalon) as he is the Japanese folktale Urashima Taro in Urusei Yatsura. Certainly, the most interesting thing about Oshii's work, specifically the Ghost in the Shell films, is not only that they borrow elements from foreign models (just as Western sci-fi borrows from anime in return), but the showily self-conscious way in which they do this.

In today's image-saturated technological global media environment, where the West is seen as just as exotic for the Japanese as Japan is for westerners, Oshii consciously cross-references elements from many cultural sources within his work. These appropriations come not directly from the culture in question itself, but previous imaginings of this culture. Whilst on a stylistic level, Ghost in the Shell most clearly borrows from Ridley Scott's Blade Runner, one must remember that Scott's film, the most significant influence on an entire generation of science fiction works, itself reconstructed its world in a cinematic film noir style, with the gleaming city of Tokyo proving a significant influence on its sleek but stark production design. One can't put it much more succinctly than in Ruh's citation of Livia Monnet: "the many visual elements and diegetic correspondences between Ghost in the Shell and Blade Runner indicate that Oshii's anime has a conscious agenda of remediating Ridley Scott's cult film, and that an intermedial conceptual fusion occurs between the two films".

As mentioned, Oshii's work is situated within the genre known as cyberpunk which began as a field of sci-fi literature in America in the 1980s pioneered by writers such as William Gibson, who in novels like Neuromancer (1984), made heavy usage of the alluring modern iconography of the city as a stand-in for any anonymous, alienating, technologically-advanced metropolis. The past twenty-five years have seen a constant discourse of both visual and philosophical ideas ping-ponged back and forth between Japanese and Western practitioners, be they novelists, animators or manga writers. Just as Gibson's ideas were taken up by Masamune Shirow in the original manga source material for Ghost in the Shell, which suffered numerous alterations at the hands of Oshii, many of these ideas from Oshii's animation were later adopted by the Wachowski brothers in the Matrix films.

Though Ghost in the Shell is the film that has attracted the most attention out of Oshii's oeuvre, Ruh's book has a lot more to say about his others, and how the elements most identified with the director were already manifesting themselves in his previous works such as Patlabor, Angel's Egg and Twilight Q 2: Labyrinth Objects File 538. One possible criticism is that the book rather glosses over Oshii's lesser-known live-action films Red Spectacles (1987), Stray Dog: Kerberos Panzer Cop (1991) and Talking Head (1992), which is a particular shame because so little has been written about them, but this is but a minor niggle.

The auteur-based approach of basing a chapter around a single work has the potential of setting the film in question in stone, sucking out its life, turning it into an intellectual exercise and killing off any alternate readings individual viewers might have. But for Ruh, Oshii's films are about "the subjectivity inherent in concepts of reality", and thankfully the author makes no secret of his own subjectivity as a viewer. As he himself points out in the introduction, this intelligent but never too highbrow or esoteric book is not intended to act as the final authority on Oshii's works. It does however serve as a valuable guidebook in the world of a director whose films are clearly in need of much further explanation and exploration.