This, the 21st volume in the Library of Living Philosophers, is more than Sir Alfred Ayer's final word on the philosophical issues that preoccupied him for more than sixty years; the list of contributors is a roll-call of some of the greatest living figures in philosophy, each expertly addressing a key problem arising in Ayer's work. Most of the critical papers are answered directly and in detail by Sir Alfred-he completed his replies to 21 of the...