For about four decades now, a course in receptor pharmacology has been given at University College London for undergraduate students in their final year of study for the Bachelor of Science degree in pharmacology. More recently, the course has also been taken by students reading for the Bachelor of Science degree in medicinal chemistry. The students following the course have relied for their reading upon a variety of sources, including original papers, reviews, and various textbooks, but no single text brought together the material included in the course. Also, almost continuously since 1993, we have organized courses for graduate students and research workers from the pharmaceutical industry.