Book excerpt: This book will serve as an introduction to Fungi, Viruses, Bacteria, and Mycoplasma to the beginners in the field. Actually the book is in intended to fulfil the long felt need of student of graduate and postgraduate level of all universities. The syllabi of all the universities have been kept in view during the preparation of the manuscript of this text. This work may also serve as laboratory manual. The present text provides a background of facts, terminology, general principle and specific fungus of world. CONTENTS Section-A Chapters Pages 1. Fungi: General Characters 2. Taxonomic Status and Classification of Fungi 3. Brief history of mycology 4. Evolution and phylogeny of fungi 5. Myxomycotina, Physarales: Physarum 6.Chytridiales:Synchytrium 7. Oomycetes, Saprolegniales:Achlya,Saprolegnia 8. Perenosporales: Phytophthora, Pythium, Albugo 9. Zygomycetes,Mucorales: Mucor, Rhizopus 10. Endomycetales: Saccharomyces 11. Eurotiales: Aspergillus, Penicillium 12. Erysiphales: Erysiphe, Sphaerotheca 13. Sphariales: Claviceps 14. Pezizales: Peziza, Morchella 15. Basidiomycetes, Ustilaginales: Ustilago 16. Uredinales: Puccinia 17. Agaricales: Agaricus 18. Lycoperdales: Lycoperdon 19.Deuteromycotina,Melanoconiales:Colletotrichum Sphaeropsidales:Macrophomina, Ascochyta Agonomycetales:Rhizoctonia, Sclerotiu 20. Moniliales: Alternaria, Cercospora 21. Heterothallism in Fungi2 22. Parasexuality 23. Sex Hormones in Fungi) 24. EdibleFungi: Mushrooms and their Cultivation 25. Economic Importance of Fungi Section –B 26. Viruses, Viroids, Prions 27. Bacteria 28. Mycoplasma 29.Multiple choicequestions fungi_and_plant pathology 30.Mycological Terminology 31.References