The content of this book is brought from a PhD Thesis titled "Modelling, Design, and Analysis of Secure Mobile Payment Systems" at Monash University, Australia. This book covers all aspects of mobile payments. It starts with introducing formal modelling of a general eletronic payment system, a mobile payment system, including the characteristics of a secure mobile payment system. Chapter 5 and 9 of this book discuss several account-based and token- based mobile payment systems which are practical for a real-world application. Chapter 7 of this book presents a formal analysis based on Accountability which is one of the most important security properties for electronic transactions. The formal logic presented in this chapter is capable of analyzing any electronic payment protocols. In chapter 8, we present a limited-use session key generation and distribution technique for Internet transactions. This book is suitable for scientists, protocol designers, and graduate students who find themselves interested in security aspects in mobile payment systems.