Beri-Beri has engaged the attention, at one time or another, of most workers in the field of tropical medicine. In the past, interest centred round the problem of the aetiology of the condition. During recent years, research. has been concerned with the biological significance, the chemical structure, and the methods of estimation of vitamin B1 and other essential food factors. My personal interest in beri-beri has been, to a great extent, clinical. The pages which follow have been devoted mainly to a description of the history, the evolution of our modern theories regarding the action of vitamin B₁, a survey of the condition itself with remarks chiefly directed' to the symptomatology, diagnosis, and treatment, and to recommendations for the future eradication of the disease. The observations I have recorded have been taken from five years of medical practice in Singapore, during which time I was fortunate enough to have entire control of an "outbreak" of beri-beri , affecting ratings of the Straits Settlements Royal Naval Volunteer Reserve. Many copious notes and photographs were taken at the time - these were unavoidably lost, and lie at the bottom of Banka Strait. As a result, the author has been forced to draw from memory for his subject matter. Personal observations and conclusions are contrasted with the opinions expressed in the more important articles sifted from the multitudinous array of literature. An attempt has been made to balance them; apparent differences have been recorded, and where possible reconciled. There is possibly no other subject where so many contradictory statements have been made; nevertheless the whole is a most inspiring story, where the ultimate destination has been reached only by long, laborious travel.