• Russell's books should be bound in two colours, those dealing with mathematical logic in red - and all students of philosophy should read them; those dealing with ethics and politics in blue - and no one should be allowed to read them.

    Ludwig Wittgenstein: Russell's books should be bound in two colours, those dealing with mathematical logic in red - and all students of philosophy should read them; those dealing with ethics and politics in blue - and no one should be allowed to read them.
    "Recollections of Wittgenstein". Book by Rush Rhees, 1984.