The annals of New Zealand art from the colonial period are scattered with unattributed works and those by artists about whom precious little in known. The unravelling of this jigsaw is left to art historians, working away quietly in archives, libraries and art museums. One as yet unsolved riddle concerns Captain Robert Marsh Westmacott. In 1929 art dealer and expatriate Kiwi Rex Nan Kivell purchased at auction from the Museum Book Store, London, a drawing book containing sixteen New Zealand topographic views and figure studies. Roughly dated at around 1840, they were part of the estate of the late Captain Westmacott (1801-1870). The majority appeared to be original works by, or copies after, Charles Heaphy, Richard Aldworth Oliver, Cuthbert Clarke and Joseph Jenner Merrett. Westmacott's Drawing Book ended up in the Rex Nan Kivell Collection in the National Library of Australia, Canberra. The circumstances surrounding its compilation remain a mystery, and both the artist and the works contained therein are largely unknown. This article describes the contents of the drawing book and the context in which is was compiled.