THE JEW OF LINZ: Hitler, Wittgenstein and the Hidden Battle for Control in the 20th Century. Kimberley Cornish. Century Pounds 20 pp284.

Frank McLynn's Jung: a biography is published by Bantam

I have never been able to see the point of Wittgenstein's Philosophical Investigations, written in his late period, with its oracular I'm-telling-you style. Remaining unconvinced by the enthusiasm of his disciples, I have always wished that somebody could explain wherein the alleged profundity was supposed to reside. With this new book I get my wish, though hardly in the way expected. If Kimberley Cornish is correct, Wittgenstein was far more important than anyone has hitherto realised, for here was a man who lived out Marx's wish :"philosophers hitherto have merely interpreted the world; the task, however, is to change it." In short, Wittgenstein was both the supreme philosophical theoretician of Marxism and one of its ablest spymasters.

The story begins in the Realschule in Linz, Austria, in 1903 when the 14-year-old Wittgenstein found himself in the same school as Adolf Hitler. In Mein Kampf, Hitler reveals that he became an anti-semite after witnessing the behaviour of a "treacherous" young Jewish boy at this school; Cornish speculates that this boy was Wittgenstein, son of a wealthy family of non-practising Austrian Jews. It has usually been considered that Hitler and Wittgenstein had nothing to do with each other at school, but Cornish unearths evidence, including a school photograph, showing that the two must have known each other well.

Cornish underlines the many similarities between Hitler and Wittgenstein. They were born in 1889, within six days of each other, both were besotted with Wagner, knew Die Meistersinger by heart and could whistle great chunks...