The book entitled ?Triterpenoids: an important bioactive class of natural products? is based on the general view about triterpenoids. This book contains background, introduction, nomenclature, chemical tests, classification, biological importance, biosynthesis, extraction, isolation, characterization of triterpenoids and bibliography. This book deals mainly with the biosynthesis, bioactivity and characterization of triterpenoids. The chemical structure of various triterpenoids including recently discovered are being given in the book. The preparation of this book has been done with great care of previous research on triterpenoids. A brief discussion from several researches has been given in the book and the bibliography has given for further reading about the topic. This book is important for students as well as phytochemists working in the field of isolation and bioactivity of triterpenoids. We hope this book would give the idea about triterpenoids and their application in medicine. We certified that the matter of this book is not original or from our own work but this is based on previously published work and the sources of the same have been cited in the text.