Keys to Lichens of North America, Revised and Expand- ed. Irwin M. Brodo (photographs by Sylvia Duran Sharnoff and Stephen Sharnoff; drawings by Susan Laurie-Bourque).

It would be hard to overestimate the importance of the 2001 publication of Lichens of North America (hereafter LNA) by Irwin Brodo, Silvia Duran Sharnoff, and Stephen Sharnoff (Brodo et al. 2001). Beautifully illustrated, LNA included both an excellent overview to lichenology—including such diverse topics as chemistry, ecology, ethnolichenology, and specimen preparation—and descriptions of more than 800 of the common and charismatic lichens of North Ameri- ca. It is the rare book that provides a good introduction to the discipline, while serving as an essential tool for lichenologists. LNA is frequently cited in journals as an authoritative source on spot tests (a chemical spot analysis used to help identify lichens) and biogeography, among other subjects, and remains a go-to reference on many species in the North American lichen flora. By putting lichenology within the reach of the average enthusiast, LNA spurred interest among amateurs (this writer included) and created a lichenological renaissance in North America. The Keys to Lichens of North America, Revised and Expanded (hereafter Keys) by Irwin Brodo significantly expands on the taxonomic scope of the original work, with taxonomic keys to 2,028 species in 382 genera, more than double the number of species included in LNA. Together, LNA and the Keys stand as the only generally accessible resources for lichen identification covering the whole of North America. And, as with LNA, the new publication will be an essential part of any lichenologist’s library, but it also will appeal to the generalist seeking to learn more about identifying these elegant, ecologically important, but often overlooked organisms