The Act of Creation is a 1964 book by Arthur Koestler . It is a study of the processes of discovery, invention, imagination and creativity in humor, science, and the arts. It lays out Koestler’s attempt to develop an elaborate general theory of human creativity.
Koestler concludes that they all share a common pattern which he terms “bisociation” – a blending of elements drawn from two previously unrelated matrices of thought into a new matrix of meaning by a process involving comparison, abstraction and categorization, analogies and metaphors. He looks at many different phenomena based on comparison (such as analogies, metaphors, parables, allegories, jokes, identification, role-playing, acting, personification, anthropomorphism etc.), as special cases of “bisociation”.
The concept of bisociation has been adopted, generalized and formalized by cognitive linguists Gilles Fauconnier and Mark Turner , who developed it into conceptual blending theory . 
Book One: The Art of Discovery and the Discoveries of Art
The Act of Creation is divided into two books. In the first book, Koestler proposes to global theory of creative activity encompassing humor, scientific inquiry, and art. Koestler’s fundamental idea is that any creative act is a bociation of two (or more) apparently incompatible frames of thought.  Employing a spatial metaphor, Koestler calls such frames of thought matrices : “any ability, habit, or skill, any pattern of controlled behavior by a ‘code’ of fixed rules.”  Koestler argues that the various forms of human creativity correspond to variations of his model of bisociation.
In jokes and humor, the audience is led to expect a certain outcome compatible with a particular matrix (eg the narrative storyline); a line punch, however, replaces the original matrix with an alternative to comic effect. The structure of a joke, then, is essentially that of bait-and-switch . In scientific inquiry, the two matrices are fused into a new larger synthesis.  The recognition that two previously disconnected matrices are compatible with the experience of eureka . Finally, in the arts and in ritual, the two matrices are held in juxtaposition to one another. Observing art is a process of experiencing this juxtaposition, with both matrices sustained.
According to Koestler, many creative breakthroughs occur after a period of intense conscious effort directed at the creative goal or problem, in a period of relaxation when rational thought is abandoned, like during dreams and trances.  Koestler asserts that all creatures have the capacity for creative activity, frequently suppressed by the automatic routines of thought and behavior that dominate their lives.
Book Two: Habit and Originality
The second book of the Act of Creation aims to develop a biological and psychological foundation for the theory of creation proposed in book one. Koestler found the psychology of his day ( behaviorism , cognitivism ) portraying man as an automaton, disregarding the creative abilities of the mind. Koestler draws on theories of play, imprinting , motivation, perception, Gestalt psychology , and others to lay a theoretical foundation for his theory of creativity.
- Reed Merrill: Arthur Koestler. In: Irene R. Makaryk (Ed.): Encyclopedia of Contemporary Literary Theory. University of Toronto Press, 1993, ISBN 0-8020-6860-X , pp. 390-392.
- Conceptual blending
- Conceptual metaphor theory
- Gregory Bateson
- Jump up^ Mark Turner Gilles Fauconnier: The Way We Think. Conceptual Blending and the Mind’s Hidden Complexities. New York: Basic Books 2002, p. 37
- Jump up^ Krikmann, Arvo (2006) Contemporary linguistic theories of humor, Folklore 33, 27-57: 29.
- Jump up^ Koestler, Arthur. 1964.The Act of Creation, p38. Penguin Books, New York.
- Jump up^ Figure 2inTerrence Deacon:The Aesthetic Faculty. In:Mark Turner(Ed.):The Artful Mind: Cognitive Science and the Riddle of Human Creativity. New York: Oxford University Press, 2006
- Jump up^ The New York Times: The Genesis of Genius; The Act of Creation . 18 October 1964