The book is concerned with renewable energy sources. In particular, it reviews the state of the art in thermal solar techniques and biomasses. The first topic treated is solar radiation, followed by the possible utilizations of solar energy through thermal solar techniques. The last part of the book relates to biomasses, starting from the definition of this wide-ranging field and how it is successfully treated by obtaining energy from biomasses, and including all the environmental aspects. Very few books treat so diffusely the advances in thermal solar technologies, especially in biomasses, a topic where there is considerable confusion due to the very wide range of related technologies.