The authors of this reference provide an updated and global view on ocean wave energy conversion for wave energy developers as well as for students and professors. The book is orientated to the practical solutions that this new industry has found so far and the problems that any device needs to face. It describes the actual principles applied to machines that convert wave power in electricity. Additionally, an historical review, state of the art of modern systems, a full scale prototype experience, and future perspectives are given. The authors are recognised researchers, and their contributions give an overall perspective of the state of the art of different technologies. The book does not intend to point to a specific technology; the market will be responsible for that. The main motivation to compile these texts is to provide, both to academia and industry, a first contact with the current status of wave energy conversion technologies, hopefully inspiring the next generation of engineers and scientists.