This popular book covers generalized estimating equations (GEEs), an extension of the generalized linear model when correlation is unknown. It remains the only book to focus specifically on this important method used in the analysis of longitudinal data. This edition features new methods, particularly regarding correlation structure and the interpretation of GEE models. It also presents updated computational material and now includes both Stata and R code for all the examples as well as corresponding SAS code. All data sets and code are available at CRC Press Online.