'One of the great books of the century' - Alan Ryan, The Times

'Few philosophershave combined such a vast width of knowledge with the capacity to produce important original ideas as he did.' - Anthony Quinton, The Guardian

'This is a work of great interest and significance, stimulating and suggestive throughout. Dr Popper's virtues are manifold. He has a great fertility of ideas. Almost every sentence gives us something to think about.' - G.C. Field, Philosophy