The present second edition of the Color Atlas of Pharmacology goes to print six years after the first edition. Numerous revisions were needed, highlighting the dramatic continuing progress in the drug sciences. In particular, it appeared necessary to include novel therapeutic principles, such as the inhibitors of platelet aggregation from the group of integrin GPIIB/IIIA antagonists, the inhibitors of viral protease, or the non-nucleoside inhibitors of reverse transcriptase. Moreover, the re-evaluation and expanded use of conventional drugs, ., in congestive heart failure, bronchial asthma, or rheumatoid arthritis, had to be addressed. In each instance, the primary emphasis was placed on essential sites of action and basic pharmacological principles. Details.