This book aims to be a bridge between elementary calculus and the most advanced courses in theory of real and complex functions. Because it embraces classical concepts and results, it can be used by maths, physics and engineering students. This book is selfcontained and it only requires basic calculus knowledge. Therefore it is considered an introduction to study general topology and continuity and differentiability of functions in several variables. The authors have written down their teaching experience, making it easy to understand, with many examples and exercises that simplify the access to Mathematical Analysis knowledge.