Ian Ridpath is the co-author (with Wil Tirion) of the 'Collins Pocket Guide to the Stars and Planets' and 'The Monthly Sky Guide' (CUP). Ian is editor of 'Norton's Star Atlas' and the 'Oxford Dictionary of Astronomy', and author of 'Star Tales'. Wil is author of 'Sky Atlas 2000'.

Wil Tirion was trained in graphic arts and has always had an interest in astronomy and especially star charts. In 1983 he became a self-employed full time Uranographer. Since then he has contributed to many atlases, books and magazines. In 1987 he received the 'Dr. J. van der Bilt-prize', a Dutch award for amateur astronomers. In 1993 this was followed by a second, more international 'award', when a minor planet was named after him: (4648) Tirion = 1931 UE.