David Deutsch is a physicist and author who is, as he puts it, "interested in anything fundamental." He discovered the first quantum algorithm and is the codiscoverer, with Richard Jozsa, of the first quantum algorithm that could solve certain problems exponentially faster than anything available to classical computer science.

Deutsch has proposed constructor theory, which postulates that all laws of nature can be expressed in terms of whether a task is possible or impossible -- a theory that extends not only to computation, but also into everything that exists. He is a proponent of the multiverse interpretation of quantum mechanics, which has the startling implication that every physically possible event exists somewhere within an infinite fabric of co-existing universes.

He is the author of The Beginning of Infinity and The Fabric of Reality.