Werner Herzog is much more than just a filmmaker. He is an adventurer, an explorer, an athlete, a guru, a daredevil man of action, a pilgrim, a keen football player and cook, a curmudgeon and a crank. He is, possibly, a complete maniac. The great Pauline Kael, in an enviably apt phrase, called him a ‘metaphysical Tarzan’. He is, almost certainly, the only director to have filmed on all seven continents, and has come close to death several times on the journey. He is a ferocious autodidact and a scholar of the classics, who carries a copy of Livy with him on every shoot. A few years ago, while being interviewed in the open air by the BBC in Los Angeles, he was shot at by a random sniper. He carried on talking while the film crew hit the floor. He thought they were pitiful cowards.

There is no other director quite like him, even if he has some perceptible affinities with Robert Flaherty, John Huston, Stan Brakhage, F W Murnau, David Lynch and David Lean. Although he uses the most advanced forms of technology, he is more a man of the late Middle Ages than the 21st century. His spiritual forebears are warlords, hermits, prophets, stonemasons and wandering scholars. He says that he would have made a good Neanderthal, and he is probably right.

Werner Herzog: A Guide for the Perplexed is a substantially enlarged version of Paul Cronin’s book of interviews Herzog on Herzog, first published in 2002. The new edition brings us up to date with what the extraordinary Bavarian has been doing over the last dozen years – a lot, actually – but the expansion has allowed the book to mutate into an entirely different beast. Whereas that short book was strictly for film buffs, this one ranges over much wider territory and deserves to reach a general readership. As the title (borrowed from Moses Maimonides) suggests, it has grown into a strange – very strange – kind of self-help book. It is also a map of Herzog’s interests and passions.

Among his passions is early music: he is enthralled by Gesualdo (about whom he has made a film) and relishes less well-known composers, such as Heinrich Schütz, Orlando di Lasso, Johannes Ciconia, Martim Codax, Francesco Landini and Peter Abelard. His tastes in literature also incline towards the recondite: the Baroque German masters Johann Christian Günther, Andreas Gryphius, Friedrich Spee and Angelus Silesius. In addition to Livy, he turns for support and inspiration to a clutch of better-known masters: Thucydides, Montaigne, Virgil, Conrad. His favourite artists are slightly more obvious: Grünewald, Bosch, Friedrich and Hercules Segers. He is, in short, not exactly a lowbrow, and every other page of the book throws out a fistful of tempting hints for his fellow autodidacts and aspiring polymaths.

Impressive as it is, Herzog’s self-forged erudition – he did not attend university and is contemptuous of modern film schools – is his least remarkable quality. At the time when Herzog on Herzog was new and a lot of cinephiles thought that his career was on the decline (it wasn’t), the two films that seemed most emblematic of him, and most expressive of his temperament, were Aguirre, the Wrath of God and Fitzcarraldo. The first was about a doomed journey down a South American river by a deranged conquistador; the second was about an obsessed Irishman who hauls a huge ship over a South American mountain.

In both cases, Herzog endangered himself, his casts and his crews by shooting in hazardous, remote locations with pitifully low budgets. And in both cases, the central character was played by the frightening but compelling Klaus Kinski. Herzog planned to kill his leading man on several occasions. Most people assumed that Kinski was Herzog’s alter ego and that the films were allegorical self-portraits of the artist as a Marlovian overreacher – mad, bad and dangerous.

The picture looks very different today. Thanks to the films he has made over the last decade, Herzog now seems a very different kind of filmmaker: ruminative, elegiac and oddly humane, in a bleak and unforgiving way. Among the best films of this later period are the poetic documentaries Grizzly Man (about a well-meaning American idiot killed by the wild bears he loved), Cave of Forgotten Dreams (about prehistoric paintings and the biological origins of art), Encounters at the End of the World (set in Antarctica), Death Row (interviews with condemned murderers) and several others. In just ten years, the wild man has matured into a wise man, and people have increasingly begun to treat him as one. Time magazine named him as one of the hundred most influential people in the world.

A man who has achieved so many and such exceptional things – against the odds, he has made over sixty films, directed operas, written books, acted a bit (his performance in the recent thriller Jack Reacher, in which he plays a Russian thug who chewed his own fingers off in the Gulag, is a blast) and now teaches a bizarre seminar on ‘Rogue’ filmmaking – deserves close attention. Werner Herzog: A Guide for the Perplexed is one of the best, the most inspirational and definitely the most unusual guides to filmmaking ever written. On page 231 there is a list of advice that, duly heeded, will do would-be directors more good than two years in film school. My favourite: ‘Carry bolt-cutters everywhere.’

But just about anyone who wishes to follow an art or craft or trade or passion can learn from this book, too. One of Herzog’s maxims is: ‘Those who read own the world; those who immerse themselves in the Internet or watch too much television lose it.’ Most self-help books tend to be a bit wet and mushy, a bit New Agey. Herzog’s self-help proposals are harsher, more challenging, and perhaps even universal: ‘Never wallow in your troubles; despair must be kept private and brief’; ‘Expand your knowledge and understanding of music and literature, old and modern’; ‘Study the law and scrutinise contracts’; ‘There will always be periods of solitude and loneliness, but you must have the courage to follow your own path.’

In an age when few people pay much attention to that fine work The Boy Scout Handbook, this guide would make an ideal gift for any thoughtful and ambitious young person. And ‘carry bolt-cutters everywhere’ is a hard-won piece of wisdom from which, surely, we can all learn. I am ordering mine now.