This book has to be considered a manual for the undergraduate student approaching the world of non-relativistic quantum mechanics. Many texts, apart their degree of detail, may result fuzzy and difficult to understand despite the familiarity of the reader with the subject. The true purpose of this book is thus to tell things in the simplest and most linear way. Actually all efforts have been focused on writing a manual firmly student-oriented. Many explanations and observations are not trivial and are indeed reported to let the student taking over elementary steps, avoiding weary time consumptions. In this way the reader will be stimulated toward more fruitful and interesting speculations.