Volume 5 of Advances in Medicinal Chemistry contains four intriguing and detailed accounts of the close interface between synthetic chemistry, structure-activity relationships, biochemistry, and pharmacology. In Chapter 1, there is a comprehensive survey of the immunophilin area specifically focussing on neuroregenerative applications in the central nervous system. In Chapter 2, there is an overview of the development of a potent analgesic compound that works via modulation of neuronal nicotinic acetylcholine receptors. In Chapter 3, there is a description of dopamine D-2 autoreceptor partial agonists as potential therapy for the treatment of schizophrenia. In Chapter 4, there is a summary of the successful program in which potent non-peptide inhibitors of HIV protease from the AIDS virus were developed.