The myasthenic syndromes are a group of disorders in which neuromuscular transmission is impaired at the motor endplate. Many of the myasthenic syndromes are congenital, but Lambert-Eaton myasthenic syndrome, which was one of the fi rst of these syndromes to be described, is associated with a tumour, mostly small-cell carcinoma of the lung, in 50–60% of patients. In 1951, severe muscle weakness was seen in a patient with bronchial neoplasm who was admitted to St Thomas’s Hospital, London, UK; this weakness disappeared almost immediately after removal of the tumour, suggesting that such neoplasms might give rise to a peripheral neuropathy. When a 47-year-old man complaining of progressive muscle weakness that fi rst aff ected his legs but later aff ected his arms and head was admitted to the same hospital 2 years later, further investigations were warranted. Upon examination, he was found to have small-cell lung carcinoma, and administration of thiopentone sodium and succinylcholine prior to biopsy led to prolonged apnoea. In the presence of normal cholinesterase activity, this was suggestive of a change in the response of the motor endplate to depolarising drugs, and investigations showed that the response at the motor endplate to tubocurarine, decamethonium, and succinylcholine was similar to that seen in myasthenia gravis. At the meeting of the American Physiological Society in 1956, Lambert, Eaton, and Rooke presented the cases of six patients with defective neuromuscular transmission that was associated with malignant neoplasms. In these patients, many of the clinical and electrophysiological features were reported to be diff erent from those seen in myasthenia gravis. A year later, Lambert and Eaton reported the electrophysiological features of the myasthenic syndrome, leading to the eponym.