A wind turbine is of course far more complicated than just a tower topped with a big fan, especially for the offshore ones. Wind energy as a green energy resource with zero fuel requirements, and thus no processing waste, has been assuming an increasingly important role in energy generation. Offshore wind farms with their steady output and low sensual impact have been gradually accepted by the public and authorities. Once built, the only cost for a wind farm is the operation and maintenance cost. Therefore, the question of how to reduce the failure rate and the operation and maintenance costs, and make offshore wind energy cheaper, is particularly pertinent, and is discussed in great detail here.This book details the various aspects of wind energy, and is accessible to the lay reader without any specialist knowledge. It explores the numerous concepts associated with offshore wind farm operation and maintenance with condition monitoring system, and vividly presents the the basics of wind energy, augmenting this with a large amount of valuable real wind farm case studies.