"'Contrary-to-fact conditionals have provided logical analysts with fascinating puzzles. (This book) has a unitary theme presented clearly and attractively for the most part with only the unavoidable minimum of formal apparatus. The theme is pursued confidently and relentlessly without evasions or qualifications." Times Literary Supplement

"This is an excellent book. It combines shrewd philosophical sense with a fine technical expertise. The statement of views is concise and forthright." Kit Fine, Mind

"This essay is a virtuoso performance." British Journal for the Philosophy of Science

"Beautifully and lucidly written and full of clever ideas. It contains very many philosophical insights and comparisons." J. J. C. Smart, Australasian Journal of Philosophy