The aim of this book is to study the growth, existence, scope and advantage of archaeal communities. These species have inhabited the earth since long and hence are witness to all the changes that have taken place since then. It is a subject of great interest as its application can change the face of microbiology in the most amazing way. The authors have done a profound study and analysis before presenting their findings as is apparent from the content. This book will serve as an advantage text for students and experts alike.