The present work is arranged in three parts: the agarics are dealt with first, the non-agarics next, both with particular reference to their major habitat preferences, and lastly a catalogue of those more specialised habitats which are frequently encountered. All parts are supported at the end by lists in tabular form of those species expected to be found in any one habitat. Keys to the major groups, families and genera, are included to widen the scope of the book and place the examples chosen and illustrated in the text in their position in classification. In the description the synonymy has been very severely pruned and only covers the commonly seen names; they are included as part of the general information under each species. In order for the student to expand unfamiliar names a list of references is added at the end of the work. The common names of the fungi, whenever possible, have been adopted from a list produced by Dr Large, the author of _The Advance of the Fungi_, an exciting tale of fungal parasites. The authorities for the names of the fungi described have been reduced to accord with the minimum requirements set out by the Code of Botanical Nomenclature. After each description a list of references to coloured plates is given and while some of these illustrations are not of the highest quality they are adequate, and, more important, they are widely available. Any technical terms appearing in the description are explained in the glossary, although they have been kept to a minimum; the difficulty of expressing colours has been overcome by consistently referring to one colour chart only, (a chart designed originally for the use of mycologists and available from Her Majesty’s Stationery Office). I have not indicated the edibility of a particular species unless there is no doubt as to the edibility of it, related species and those species with which it might be easily confused. Many fungi are notoriously difficult to identify and when one has approximately 3,000 species of larger fungi in the country the task is even more difficult. It would be folly therefore to indicate edibility for all the fungi described in a book such as this; the golden rule which should be adopted is not to eat any of the fungi one collects in the woods and fields. A fault of most popular treatments is that they are biased towards the human diet and selection of species is done on this basis; in the present work selection of examples within the 270 pages has been difficult and two factors have been particularly considered to ensure that (i) representatives of all the major groups of fungi and genera have been covered and (ii) a coverage has been attempted of all the common ecological niches.