This book describes maturity in understandable and practical terms. If you want to know what it means to be mature, this book is for you. If you want to know how to live a mature life, this book is for you. If you want to grow up or know what it means to grow up, this book is for you. With all our means of communication and education, how is it possible that many fundamental concepts and principles continue to remain a secret or a mystery to most people? What kind of educational system can call itself education and fail to discuss and explore fundamental human qualities like maturity? The research for this book uncovered a myriad of different ways of approaching the same basic answer for the secret of maturity: Maturity is responsibility. Most of the answers to What is maturity? come from either psychology or philosophy. The answers are listed or briefly described throughout the text, but it is your job to decide what to do with all the answers. So be responsible for how you assimilate the answers and put them into practice. Quite a few of the paragraphs in this book summarize concepts that are expounded in entire volumes elsewhere. Since this book is so condensed, it will be most effective after it has been read and studied many times.