James Wilson was an early nineteenth-century astrologer. Very little is known of his life except that he published what became the seminal work from which modern astrology would develop. His great, comprehensive work, The Dictionary of Astrology, appeared in 1819. The volume included evidence of Wilson's extensive research into astrology and the teaching of astrology over the centuries. His work was based largely on his close reading of the works of Ptolemy, Placidus, and other Classical astrologers. For generations his Dictionary was considered the finest of all astrological ditionaries. Wilson's goal, as stated in his work, was to force a student of astrology to think about some of the most basic assumptions in astrology. He clearly rejected everything for which he could find no evidence. He was especialy interested in horary astrology, a branch of astrology that assumes whenever a question is asked, the answer is reflected in the position of the solar system planets at a given moment. In 1820, Wilson published a set of astrological tables and charts required for an astrologer to construct a horoscope. Several years later he published a new edition of Ptolomy's Tetrabiblos, the work from which all Western astrology derives.

Wilson's Dictionary went into several editions and was regularly reprinted throughout the nineteenth century, influencing generations of British astrologers. Wilson was apparently a very secretive individual, concealing his origins, personal, and even professional life, much to the frustration of later researchers and biographers. His fame, rather, rests on the legacy wrought by his research and publications.