This book is useful for under graduate students, post graduate students and Research scholars for those who are working in the area of Cloud Computing and Network Security. Chapter 1 deals with Introduction to Cloud Computing. Chapter 2 deals with existing work related to Cloud Computing. Chapter 3 Fuzzy logic system in Cloud Computing for Trust and Reputation factor. Chapter 4 Neural Network in Cloud Computing for Trust and Reputation factor. Chapter 5 Hybridization of Rough and Fuzzy set theory.