Selby was an English ornithologist, botanist, artist and landowner. He is best known for his Illustrations of British Ornithology (1821–1834), the first set of life-sized illustrations of British birds. He also wrote Illustrations of Ornithology with William Jardine and A History of British Forest-trees (1842).
Many of the illustrations in his works were drawn from specimens in his collection. In addition to the above works he contributed to Jardine's Naturalist's Library the volumes on the Pigeons (1835) and the Parrots (1836), the latter illustrated by Edward Lear. He was for some time one of the editors of the Magazine of Zoology and Botany. His collections were sold in 1885 and became dispersed. The South African birds collected by Andrew Smith went to the Zoology Museum of the University of Cambridge.
Selby was born at Alnwick in Northumberland, a son of the Beal and Twizell House, Northumberland branch of the Selby family and studied at University College, Oxford. He married Lewis Tabitha Mitford and they had three daughters. He died at Twizell House and was buried in Bamburgh churchyard.