Abstract: The purpose of this talk is to review a method used to obtain quantitative properties of Lyapunov exponents of quasi-periodic linear cocycles. The method consists of an analytic tool - a large deviation estimate for the iterates of the cocycle and a criterion for establishing the growth of long products of matrices, called the avalanche principle. These tools were initially developed for 2-dimensional Schrodinger cocycles by M. Goldstein and W. Schlag, and recently extended and applied to a more general setting by P. Duarte and I. The hope is that we might be able to modify and adapt this method to linear cocycles with other types of base dynamics.