James Ian Craig Boyd (31 March 1921 – 20 February 2009) was an English author and narrow-gauge railway historian. Boyd spent a lifetime researching and writing on narrow-gauge railways. His books on narrow-gauge railways in North and Mid Wales, the Isle of Man and Ireland are considered to be standard works on the subject. His books, published by The Oakwood Press since 1949, are rarely out of print, reflecting their importance to, and popularity with, railway historians and enthusiasts.