The magnificent monograph of the British Cretaceous echinoids (sea urchins) by Thomas Wright (1809–84) was to be followed by a similar work on the asteroids (starfishes). Sadly, Wright died in the early stages of this project, leaving only notes and some plates, but it was taken up by Walter Percy Sladen (1849–1900), who completed two parts before ill health interrupted his previous productivity. William Kingdon Spencer (1878–1955) became the third authority to be involved, finishing the work in a further three parts and also expanding the scope to include the ophiuroids (brittle stars). All three contributors were amateurs, variously a surgeon (Wright), independently wealthy (Sladen) and HM Inspector of Schools in Suffolk (Spencer). Originally published in five parts between 1891 and 1908, Sladen and Spencer's text, embellished by many fine plates, is a monument to two of the rarer, yet most attractive, groups of Cretaceous fossils.