Comparative Genomics, Volume 1, contains the first four of seven sections. In the first section, the reader is introduced to genomes via a number of visualization tools that allow one to browse through a particular genome of interest. The second and third sections deal with comparative analysis at the level of individual sequences, and present methods useful in sequence alignment, the discovery of conserved sequence motifs, and the analysis of codon usage. The fourth section deals with the identification and structural characterization of non-coding RNA genes. In the second volume, the fifth section describes a number of tools for comparative analysis of domain and gene families. These tools are particularly useful for predicting protein function as well as potential protein-protein interactions. In the sixth section, methods for comparing groups of genes and gene order are discussed, as are several tools for analyzing genome evolution. Finally, the seventh section deals wit.