Permanent Present Tense,By Suzanne Corkin. Allen Lane, £20

One of the scandals of 20th-century medicine was the attempt by surgeons to alleviate symptoms of psychiatric and neurological disease by removing sections of the brain. In the first half of the century, drugs to control symptoms in psychiatric conditions such as schizophrenia, depression and anxiety were few. Suzanne Corkin's book starts with a history of this neurosurgery. One example is that of Rosemary Kennedy, sister of JFK, whose "bad behaviour" at school precipitated referral for surgery. The resultant frontal lobotomy left her so handicapped that she was institutionalised for the rest of her life.

Corkin's account includes chilling details about the gung-ho attitudes of some surgeons. Walter Freeman carried out more than 3,000 lobotomies, many forcibly. He lost operating privileges at three hospitals because of major adverse effects, but continued operating.

Neurosurgery for neurological conditions such as epilepsy came in later, and this is where the author's identity becomes important. One of the earliest patients treated with surgery for epilepsy was Henry Molaison. In 1953, aged 27, he underwent bilateral removal of the medial (ie inner) surface of temporal lobes including, crucially, the hippocampal gyrus: an area now closely associated with memory formation. The surgeon also removed the amygdala, now known to be associated with drives such as hunger, thirst and sex, and pain perception. Following the surgery, Henry lost his ability to store new memories. Corkin is a neuroscientist who met Henry in 1962, and worked with him for many decades.

Henry was a valuable asset to science since the exact defects in his brain were known but his cognitive abilities were intact. He stated that he wanted to help others, and the tests carried out over the years, mostly on memory, have greatly increased understanding.

Corkin cites the fascinating tests which ascertained many hitherto unknown facts about memory. Her warm, engaging book explains the science in a way accessible to scientists and laypeople alike. Throughout, the genial Henry maintains his individuality.