Lambert Adolphe Jacques Quetelet FRSFor FRSE (French: [k?tl?] (listen); 22 February 1796 – 17 February 1874) was a Belgian astronomer, mathematician, statistician and sociologist.
He founded and directed the Brussels Observatory and was influential in introducing statistical methods to the social sciences.
His name is sometimes spelled with an accent as Quételet.
He founded the science of anthropometry and developed the body mass index scale, originally called the Quetelet Index.