From the preface:
"This book is intended to serve as an introduction to the study of the lichens of Israel and as a guide to their identification. Research in this field was initiated relatively recently (1936) by the pioneering work of Professor Israel Reichert. For the sequential order of the families and genera, I have followed, with only minor deviations, the scheme proposed by Hale (1967).
The descriptions of species and varieties are based on my own investigations. The majority of these descriptions are illustrated by photographs, and in some cases by drawings. For the classification of the families and genera I have used the full range of diagnostic characters as they appear in the relevant literature, even though they are not always fully represented in the particular species surveyed.
The distribution recorded is based on data from the pertinent literature. The two maps and the terms employed for recording the local and general phytogeographical distribution of the species have been taken from M. Zohary and N. Feinbrun-Dothan, Flora Palaestina, Jerusalem 1966.
A special effort has been made to identify the chemical constituents of some of the lichens. ‘These investigations were made by the usual techniques described in the works pertaining to this field (spot tests, microcrystal tests, paper chromatography and thin layer chromatography).
This study does not claim to be exhaustive. I am aware of a number of shortcomings, especially in two difficult groups – the Verrucariaceae and the subgenus Aspicilia. The comprehensive survey of these two groups would have been a prohibitively lengthy task."