Lawrence Sutcliffe Walsh was born on 7 January 1916 in East London, South Africa, the son of Richard Chadwick Walsh, an engineer, and his wife Maria, née Schofield. He was educated at Selbourne College. In order to study medicine it was first necessary for him to qualify in pharmacy. Later he obtained a scholarship which enabled him to enter Cape Town University where he graduated MB, ChB in 1944 with the gold medal for the most distinguished student. After postgraduate training in medicine and surgery he spent a period as an anaesthetist at Groote Schuur Hospital, Cape Town. Seeking wider horizons he embarked on an overland journey from Cape Town to England in 1947. He was appointed house surgeon to WB Gabriel and to Hamilton Bailey and then to Wylie McKissock at the National Hospital for Nervous Diseases. His training there gave him scope for research in hydrocephalus and trigeminal neuralgia. He obtained his FRCS in 1949. A research fellowship at St George's Hospital then enabled him to study the problems of cerebrovascular disease especially those due to intracranial aneurysm. His contribution lead to a more orderly and scientific approach to their treatment. He then spent a period of study in Stockholm in order to pursue his interest in stereotactic surgery. On his return he obtained a research fellowship at the Royal National which resulted in his clarification of the case selection and surgical techniques required in many movement disorders, notably Parkinson's disease and he appeared on the BBC Television series *Your life in their hands* describing the surgical treatment of this disorder. In 1957 he was appointed consultant neurosurgeon at Atkinson Morley's Hospital and soon afterwards to the area neurosurgical centre at Guildford. These appointments were followed in 1965 by that of consultant neurosurgeon to the National Hospital for Nervous Diseases and to St Mary's Hospital. Throughout these appointments he continued his researches into stereotactic surgery and its application to biopsy of tumours and the treatment of pituitary tumours and craniopharyngiomas by radioactive implants. His inquiries into cerebrovascular disease continued and he played a major part in the cooperative studies sponsored by the National Institutes of Health in the United States. Recognition of his work came when he was elected a corresponding member of the American Association of Neurological Surgeons in 1969. He married Mary Evelyn Thomas in 1952. They had three children, Richard, Gillian and Robin; the elder son is a Fellow of the College. He retired in 1981 but sadly was soon stricken by an illness that prevented him from enjoying his well earned leisure, suffering with great fortitude, forbearance and humour until his death on 16 March 1986.