This volume contains 33 peer-reviewed contributions by 70 authors, many leaders in their field, and is wide-ranging in its taxonomic scope. A total of 38 new taxa (35 species, 2 genera, 1 family) are described, including 8 honorific names for Tom Nash in recognition of his lichenological legacy. Taxonomic treatments cover regions throughout the world, including coastal Chile (Niebla, Sclerophyton), Îles Kerguelen (Aspiciliopsis, Placopsis), the Sonoran Desert (Roccella), the Southern Hemisphere (Buellia subalbula-group), Thailand (Malmidea), and the West Indies (Phyllopsora). Molecular phylogenetic analyses are also integrated in 7 studies and 8 include taxonomic keys. Lichens and lichenicolous fungi from over 30 genera are covered (e.g., Acarospora, Bulbothrix, Caloplaca, Candelaria, Canoparmelia, Circinaria, Cliostomum, Endococcus, Enterographa, Holospora, Lecidea, Lichenochora, Merismatium, Niebla, Parmotrema, Pseudopeltula, Punctelia, Rinodina, Solenopsora, Usnea, Xanthoparmelia), many wonderfully illustrated (40 b/w-figures and 120 images in 16 colour plates). Numerous other figures and tables document distributions, chemistry, and morphology for the taxa included. The volume dedicated to Thomas H. Nash III on the occasion of his 65th birthday also offers analyses and thought provoking discussion related to aspects of lichen ecology and the use of lichens in biomonitoring, and a biography and bibliography spanning the career of T.H. Nash III (~40 yrs.) are also included.