The suppressed version of the map prepared for Captain James Cook’s official account of his third voyage. The remainder of Cook’s third voyage of discovery returned to England in 1780, without Cook who had been killed on Hawaii in 1779. The official account of it was published in 1784 and included a somewhat inferior map of the northern Pacific which did not reflect the discoveries made. Why was that?Helen Wallis studied the papers of the voyage and published a paper in 1978 which shed light on how troubled the map of this region ended up being. The papers referred to two versions, the unpublished one remained unidentified until one appeared at a Christie’s auction as part of a large collection of proof plates for the work. The most notable difference is the presence of extensive knowledge of the interior of Canada, displaying the results of Samuel Hearne’s journey through Canada 1770-72 which resulted in the discovery of the Arctic Ocean to the north of Canada. The results of his journey were not otherwise published until 1795. The chart displays Cook’s route and notes the dates of each position as detailed in the Explanation. The shores of both Northwest America and Asia were greatly improved by the survey work undertaken by Cook between 1778 and 1779. The task of writing the official account fell to Captain James King whilst the preparation of the charts was the undertaking of Lieutenant Henry Roberts (1756-96), masters mate on the ‘Resolution’. The ultimate arbiter was the First Lord of the Admiralty, the Earl of Sandwich. He was a supporter of Cook; however, his position was taken over by Lord Keppel in 1782 who left more of the control over the maps to Alexander Dalrymple and Sir Joseph Banks. The debates became heated. A letter written by Captain King on 13 December 1783, highlights this stating “The [Dalrymple] & Sir Jos. [Banks] are determined to have their Polar map & not mine, & to have none of the Hudson Bay Companies discoveries inserted saying that these things are only proper in the General Chart.”We now know that Robert’s chart was completed as early as July 1783 and passed to the mapmaker William Faden (1749-1836) for engraving by William Palmer (1739-1812), “a version more elaborate than that in the authorized atlas”. It would be published by Faden in 1784. Apart from the interior details this map contains over a dozen placenames in Alaska not found on the official map.This map was known to exist; an example was in the famous Thomas Streeter sale in the 1960s. However, its source and role in the Cook drama did not unfold until 1985 and the sale at Christie’s. That proof copy was acquired by the British Library. In 1794 Faden issued an updated version drawing on Russian sources. Campbell (1985) ‘A Cook Mystery Solved’; Christie’s London 17 April 1985 lot 257; Falk (1983); Howgego (2003) C175 & H51; Kershaw (1993-98) 1143; Stevens & Tree (1967) 64a; Streeter Sale (1969) VI, no. 3479; Wagner (1937) 700; Wallis (1978) ‘Publication of Cook’s Journals: See New Sources and Assessments’; Worms & Baynton-Williams (2011).