My first challenge in reviewing this book was moving beyond the outer cover. I appreciate that this book is the latest output in a long series of textbooks that is both scientifically and historically important, but perpetuating the myth that fungi (lichenized or not) are plants for the sake of historical precedent confuses students and does no credit to the memory of the great German biologist, Adolf Engler. Nevertheless, I gritted my teeth and opened the volume, and was much rewarded by the content if not the title.

The book contains, in order of appearance: a (rather too) brief list of abbreviations, a short and lucid account of the characteristics of the phylum along with key references and a synopsis of the classification. The systematic arrangement takes up by far the bulk of the volume and is divided into three subphyla, 18 classes, 97 orders (along with miscellaneous lineages given similar if unofficial rank) and 406 families. Each family treatment receives a description, a list of significant constituent genera and a paragraph of taxonomic notes. An index to taxa completes the volume. The systematic arrangement is based on an updated version of that presented in 2010 in the online publication Myconet (https://www.fieldmuseum.org/myconet).

Compressing the current knowledge of the taxonomy and phylogenetics of the Ascomycota into three hundred or so pages is an enormous achievement. In the early days of fungal taxonomy, where the major taxa were defined using a small suite of artificial characters (including the lichenized condition), it was straightforward to write such an account, though the results are now recognized as rudimentary. In the last twenty years, however, our understanding of fungal evolution and phylogenetics has undergone a revolution that continues with little sign of abatement. New orders and families are recognized on an almost weekly basis, complicating immensely the task of compiling this book. Not all will survive the test of time (I rather liked the comment on page 47 that the number of families and orders appear hypertrophic) but the broad structure of the new phylogenetic system will remain for some while.

Perhaps the biggest challenge in compiling a volume such as this is to reflect the most modern phylogenetic thinking, while at the same time rejecting trivial changes and linking back to more familiar classifications. Broadly speaking the authors have done an admirable job here, though with occasional aberrations (e.g. the inclusion of the Geoglossaceae within the Leotiales (Leotiomycetes) rather than in the phylogenetically and phenotypically distinct Geoglossomycetes). Reflecting evolutionary realities, lichenized taxa are spread throughout the subphylum Pezizomycotina, within six of the twelve classes and occupying around a quarter of the main body of text.

What’s not to like? The slavish inclusion of “authors” for all names, without providing references to the publications, makes the text difficult to read, wastes space and does not properly credit the originators of taxa. Other abbreviations irritate also, especially when contained within sentences that are otherwise plain English. The text lurches in and out of what might be described as Germanglish in places. The coloured illustrations are too small, and are almost exclusively of external appearance rather than diagnostic features. They are quite beautiful but decorate rather than inform. But all of these are minor criticisms and should not detract from the overall picture.

The pace of progress is such that this book is already out of date (and will probably become even more so in the interval between writing this review and it appearing in print). We are currently in the throes of a second revolution with the abandonment of the dual nomenclatural system for fungi. This will have a very limited effect for lichenized groups, but the full integration of anamorph taxa into the system of the Ascomycota will result in further seismic changes. Perhaps the whole content of this volume is better suited to publication as an online database and I hope that after a suitable interval its contents will be included in a future edition of Myconet. In the meantime, we must all be most grateful to the authors and publisher, and those with large pockets will not be disappointed.