This volume celebrates the 100th issue of Bibliotheca Lichenologica, ‘a milestone in lichenological publishing’. Since it's inception in 1973, with the late Joseph Poelt as it's first editor, succeeded from 1983 by Volkmar Wirth, the publisher Jörg Kramer has provided a magnificent service in providing a regular outlet for lichenological publications. Many of these have been long and detailed monographs which are difficult to publish elsewhere.

This celebration is made up of 18 chapters by 37 authors, all in English. These authors deal with aspects of lichenology from all over the world, and their names will be familiar to most of us. As with most compendia of this type, not all chapters will interest everyone, or to put it another way, there is something here for everyone.

Kärnefelt and Wirth start off with a chapter on the history of Bibliotheca Lichenologica 1973–2009, principally reviewing the key works in the series, and listing them all. This provides a brief but fascinating history of lichenology over that period. Kärnfelt goes on to a more controversial topic in a review ‘Fifty influential lichenologists’ which has brief biographies and fascinating photographs of the chosen persons. But, too many worthy souls are left out – maybe he should have chosen 100, or even 200? This controversial theme is continued in Lücking et al's ‘How many tropical lichens are there … really?’ Their numerical analysis predicts 14 000 lichens for the entire tropics and 28 000 worldwide. The last estimate greatly exceeds the prevailing global estimate of 20 000.

There are four papers dealing with ecology and distribution, including marine lichens of the Baltic, southern hemisphere Teloschistaceae, the Namibian desert and the Arctic-Alpine community Thamnolietum vermicularis. One paper deals with the physiological experiments on cultured mycobionts of Rhizocarpon. Molecular phylogeny and growth rates get one chapter each. Xanthorioid Teloschistaceae are here divided into seven world-wide groups, illustrated with excellent colour plates, while evolution of lichen associations in the Lobariaceae discusses the Gondwanaland ancestor of all Sticta species, at least in the Southern Hemisphere. Systematics and phylogeny receive the most attention with seven chapters dealing with new genera in the Arthoniales, new species from the Ukraine, Polysporina from Asia, ephemeral lichens in the Thelocarpaceae and Vezdaeaceae and the new genus Traponora from the tropics. A further Teloschistaceae chapter deals mainly with Australian Caloplaca and some Xanthoria sensu lato, again with excellent colour photographs. One of these systematics chapters is outstanding, ‘A key to European Usnea species’ by Randlane et al. This chapter of 43 pages, is alone worth the price of the book as it has colour photographs of each taxon together with detailed pictures of critical morphological features inserted at relevant points in the text. Finally, radial growth of lichens in South-East Greenland is dealt with, but the word ‘Greenland’ is missing from the contents page – a rare slip in an otherwise typo-free production.

In summary, this is an excellent publication with a very high standard of production and colour photography. Some of the chapters will be regularly consulted by me. I particularly enjoyed the freedom given for authors to express potentially controversial views. I would like to congratulate the publishers on the excellent service their publications have provided to the lichenological community, and hope their efforts will continue for the benefit of future generations.