abstract: i) I first plan to introduce Glauber dynamics for the Ising model on a general bounded degree graph G. When G is the hypercubic lattice Zd I will show that for d>1 the existence of multiple Gibbs measures at low temperature is reflected in a dramatic slowing down of the dynamics. Along the way I will review some of the most common methods (comparison arguments, paths argumenst and coupling) to bound the mixing time of reversible, continuous time Markov chains; ii) I will then illustrate the problem of analyzing the Glauber dynamics inside one specific phase for G the hypercubic lattice or a regular rooted tree; iv) I will finally discuss the connection between spin models on trees and recontruction problems on noisy channels.