A. J. Ayer, who died in 1989, was acknowledged as one of Britain's most distinguished philosophers. In this memorial collection of essays leading Western philosophers reflect on Ayer's place in the history of philosophy and explore aspects of his thought and teaching. The volume also includes a posthumous essay by Ayer himself: 'A defence of empiricism'. These essays are undoubtedly a fitting tribute to a major figure, but the collection is not simply retrospective; rather it looks forward to present and future developments in philosophical thought that Ayer's work has stimulated.