A Systematic Study of The Lizards of The Deppei Group (Genus Cnemidophorus) in Mexico and Guatemala by William E. Duellman and John Wellman provides a comprehensive analysis of the lizards of the deppei group. The text covers the introduction, materials and methods, scutellation, coloration, sexual dimorphism, and systematics of the deppei group, including definitions, historical review, and keys to species and subspecies identification. The study includes detailed accounts and taxonomic classifications of each subspecies, such as Cnemidophorus deppei, Cnemidophorus lineatissimus, and Cnemidophorus guttatus, along with their respective geographical variations, dorsal patterns, and ontogenetic changes in color pattern. The book concludes with a discussion and summary of findings, alongside illustrations and figures depicting the various lizard species and their characteristics. This work aims to clarify the complex systematics within this genus, a challenge previously noted by herpetologists due to the significant variability and overlap between species.