  This article is a brief guide to the field of algorithmic information theory
(AIT), its underlying philosophy, and the most important concepts. AIT arises
by mixing information theory and computation theory to obtain an objective and
absolute notion of information in an individual object, and in so doing gives
rise to an objective and robust notion of randomness of individual objects.
This is in contrast to classical information theory that is based on random
variables and communication, and has no bearing on information and randomness
of individual objects. After a brief overview, the major subfields,
applications, history, and a map of the field are presented.
