The eleventh edition of Basic & Clinical Pharmacology is a new book in two important ways. First, the addition of new Associate Editors to the editorial group has increased currency, depth, and breadth of coverage; second, conversion to fullcolor style has increased the clarity of presentation and total information content. At the same time, the overall organization has been improved and the educational content of previous editions has been expanded. As in prior editions, the book is designed to provide a comprehensive, authoritative, and readable pharmacology textbook for students in the health sciences. Frequent revision is necessary to keep pace with the rapid changes in.