Ludwig Wittgenstein. The Duty of Genius (Jonathan Cape, London, 1990) and

Bertrand Russell: The Spirit of Solitude (Jonathan Cape, London, 1996).

Michael Ignatieff,

Isaiah Berlin (Chatto and Windus, London, 1998).

Ben Rogers,

A. J. Ayer. A Life (Chatto and Windus, London, 1999).

Rudiger Safranski,

Martin Heidegger. Between Good and Evil (Harvard University

Georg Lukács,

Soul and Form (Merlin, London, 1974).

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