Svetlana Bizjajeva and Jimmy Olsson General State Space Markov Chains Abstract: The theory of countable state space Markov chains is a standard element of graduate courses in probability and is familiar to most people in the field of mathematical statistics. The aim of the talk is to, with the theory of countable spaces as a starting point, present an overview of the corresponding general state space theory. The survey is based on the pioneering work "Markov chains and stochastic stability" by Meyn and Tweedie (1993) and starts with a presentation of the basic definitions and properties such as transition kernels, the strong Markov property and irreducibility. This is followed by a description of how parts of the theory of general spaces can be transferred to that of countable spaces through the concept of atoms and the Nummelin splitting technique. It then passes on to a discussion of stability structures such as transience/recurrence, Harris recurrence, invariant distributions, regularity and drift conditions, and ends with some results on ergodicity, that is the convergence of the distribution of the chain to its stationary distribution.