The Act of Creation begins where this view ceases to be true. Koestler affirms that all creatures have the capacity for creative activity, frequently suppressed by the automatic routines of thought and behavior that dominate their lives. The study of psychology has offered little in the way of an explanation of the creative process, and Koestler suggests that we are at our most creative when rational thought is suspended - for example in dreams and trance-like states. Then the mind is capable of receiving inspiration and insight.

Taking humor as his starting point, Koestler examines what he terms 'bisociative' thinking - the creative leap made by the mind that gives rise to new and startling perceptions and glimpses of reality. From here he assesses the workings of the mind of the scientific or artistic genius. The general reader as well as the reader with a deeper knowledge of the topics covered will find this richly documented study of creativity both illuminating and compelling.