The book presents creative problem solving techniques with particular emphasis on how to develop and train inventive skills to students. It presents an array of 24 carefully selected themes from elementary mathematics: arithmetic, algebra, geometry, analysis as well as applied mathematics. The main goal of this book is to offer a systematic illustration of how to organise the natural transition from the problem solving activity towards exploring, investigating, and discovering new facts and results. The target audience are mainly students, young mathematicians, and teachers.