Rather than rehashing basic information -- such as command syntax -- already available in other publications, this book focuses on important security and audit issues, business best practices, and compliance, discussing the important issues in IBM mainframe security. Mainframes are the backbone of most large IT organisations; security cannot be left to chance. With very little training available to the younger crowd, and older, more experienced personnel retiring or close to retiring, there is a need in mainframe security skills at the senior level. Based on real-life experiences, issues, and solutions to mainframe security from the author's three decades of practical experience as a mainframe security practitioner, this book fulfils that need.