This book offers an essential introduction to modern portfolio theory. The book provides a number of simple, practical examples to allow the reader to apply the theoretical concepts presented in each chapter. A portion of such practical cases are worked out in Excel and made available via the publisher's companion website Mybook. The book takes inspiration from Markowitz’ classical mean-variance, it then proceeds to develop modelling tools of increasing sophistication that eventually take into account the role played by generic risk-averse preferences. The book also explores a few advanced topics: the use of multi-factor asset pricing models and the role of background risks and human capital. The book is tailored for a course at MSc level.