The Diels-Alder reaction mechanism was first reported in 1928 and in the last 70 years has become one of the most commonly used and studied methodologies in organic chemistry. The reaction, which involves the addition of a diene to an alkene to form a six-membered ring, is particularly important in the synthesis of compounds of practical interest such as drugs, dyes, polymers, fragrances, agrochemicals and fine chemicals. The experimental procedure is very simple with generally good yields and minor side reactions. The use of organic solvents is not always necessary - an important factor when considering greener synthetic options. This book focuses on practice, describing procedures and techniques and as well as reporting on industrial applications. Graphical illustration presents the concepts in a clear and concise format, covering procedures and techniques employed to realize selective and clean syntheses based on the Diels-Alder methodology.