The intention of this book is to provide an impression of all aspects of p- tovoltaics (PV). It is not just about physics and technology or systems, but it looks beyond that at the entire environment in which PV is embedded. The ?rst chapter is intended as an introduction to the subject. It can also be considered an executive summary. Chapters 2–4 describe very brie?y the basic physics and technology of the solar cell. The silicon cell is the vehicle for this description because it is the best understood solar cell and also has the greatest practical importance. A reader who is not interested in the ph- ical details of the solar cell can skip Chap.2 and still understand the rest of the book. In general, it was the intention of the authors to keep the book at a level that does not require too much previous knowledge of photovoltaics. Chapter5isdevotedtoothermaterialsandnewconceptspresentlyunder- velopment or consideration. It intends to provide an impression of the many possibilities that exist for the conversion of solar radiation into electricity by solid state devices. These new concepts will keep researchers occupied for decades to come. Chapter 6 gives an introduction to cell and module techn- ogy and also informs the reader about the environmental compatibility and recycling of modules. The following chapters are devoted to practical applications. Chapters 7 and 8 introduce systems technology for di?erent applications. The envir- mental impact of PV systems and their reliability is the subject of Chap.9.