The core belief underlying this book is that the most useful and effective models to strengthen our intelligence are system ones, developed following the logic of Systems Thinking. Such models can explore complexity, dynamics, and change, and it is the author's view that intelligence depends on the ability to construct models of this nature. The book is designed to allow the reader not only to acquire simple information on Systems Thinking but above all to gradually learn the logic and techniques that make this way of thinking an instrument for the improvement of intelligence. In order to aid the learning and practice of the Systems Thinking discipline, the author has abandoned a rigid formal language for a more discursive style. He writes in the first person, with an ample number of citations and critical analyses, and without ever giving in to the temptation to use formal mathematics.