First edition. One of the important works expounding logical positivism and verificationism by Sir Alfred Jules Ayer (1910-1989). This work was in many ways a follow up to his seminal Language, Truth, and Logic (1936), and delves further into the conundrum of scepticism versus certainty.

Ayer was eminent in his field, from 1959 until his retirement in 1978 holding the Wykeham Chair, Professor of Logic at Oxford, as well as being notoriously gregarious and extroverted, marrying three women, one twice, and constantly floated in high social circles. During the Second World War he was an MI6 agent, about which almost nothing is known, and continued to show his progressive and just nature during the rest of his life.

First edition; 8vo (22.5 x 15 cm); discreet previous ownership inscription and bookseller's ticket to front endpaper, touch of spotting to edges otherwise internally clean; publisher's blue cloth, gilt lettering to title, original price-clipped dust-jacket, a little rubbing, small chips to spine, a very good copy; x, 258pp.