Book review on two volumes of: Flora of Lichenicolous Fungi Volumes 1 – Basidiomycetes Volumes 2 – Hyphomycetes Paul Diederich, Ann M Millanes, Mats Wedin, James D Lawrey Luxembourg National Museum of Natural History, 2021 ISBN: 978-2-919877-26-3 Hardback 351 pp. £38.00 from www.summerfieldbooks.com and other booksellers. Paul Diederich, Damien Ertz, Uwe Braun Luxembourg National Museum of Natural History, 2024 ISBN: 978-2-919877-27-0 Hardback 544 pp. £42.00 from www.summerfieldbooks.com and other booksellers.