Section 12 of a tentative books on Markov chains with examples of application of Gibbs sampling.
The Gibbs sampler is an algorithm for generating random variables from a marginal distribution indirectly, without having to calculate the density. Gibbs sampling is based only on elementary properties of Markov chains.
The simple case of a ( 2 \times 2 ) table with multinomial sampling clearly illustrates the Markov chain nature of the process.
The simple case of a bivariate normal table with Gibbs sampling clearly illustrates Gibbs sampling for continuous distributions.
A simple Bayesian model for a spam filter illustrates typical Gibbs sampling.