Comparative Genomics, Volume 1, provides a collection of robust protocols for molecular biologists beginning to use comparative genomic analysis tools in a variety of areas. Volume I 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 - this class of genes is particularly difficult to predict, and discovery of these elements is almost completely reliant on comparative genomics. Given the tremendous increase in available biosequence data over the past ten years, Comparative Genomics, Volume 1, is timely, comprehensive, and novel. A companion Volume 2 is also available from Humana Press.