This book principally covers the latest development of research on microfungi from both systematic and practical aspects. Microfungi are in our daily life, but we normally do not realize their presence. Without microfungi we would not be able to enjoy our baked food, fermented food, preserved food, alcoholic beverages, and access to some modern medication, such as penicillin and cyclosporine, which are secondary metabolites of microfungi. Recent advances in mycology presented in this book will be useful to identify the needs in mycological research and to determine the direction or niches for future research.