Book excerpt: Nitric oxide is a highly potent regulatory molecule with great pharmaceutical potential. This handbook fills a real gap in combining the chemistry of nitric oxide releasing substances with their practical applications in biology and drug design. It covers all classes of nitric oxide donors, from organic nitrates to nitroso compounds, guanidines and metal-NO complexes. In addition to a detailed treatment of the chemistry of NO donors, numerous examples of successful diagnostic and pharmacological applications are discussed, as well as further therapeutic targets for these substances.