As a student, I used an earlier edition of this book for identifying fungi in my mycology class at the University of Minnesota. The addition of photos in the front of the book are a welcome improvement over the original text. Multiple similar organisms are pictured on the same page and this helps to differentiate between them for identification.
Link to book: Illustrated Genera of Imperfect Fungi 4th (fourth) Edition by Barnett, Horace Leslie, Hunter, Barry B. published by Amer Phytopathological Society (1998)
The book is useful for both the beginning mycologist focusing on indoor air and the plant pathologist. The line drawings aide in identification. The addition of a 10 micron scale to each of the drawings would also make it even more useful.
This book provides an excellent companion to Identifying Filamentous Fungi and The Genera of Hyphomycetes.