Captain James Cook made three voyages to the South Pacific between 1768 and 1779 and on each occasion carried ‘Secret Instructions’ from the British Admiralty. These contained an outline of the route of the voyage, described the activities he and his men were to undertake, and the manner in which he was to report his progress. They were secret in that they held the real intentions and plans for the voyage, while other papers issued would be made available on demand to show Cook’s authority for his command and the enterprise. On his first voyage, Cook sailed in the Endeavour to Tahiti to assist in the scientific observation of the transit of the planet Venus and then sailed south in search of the fabled ‘Great Southern Continent’. 
Nathaniel Dance-Holland, James Cook, c1775
The Secret Instructions, dated 30 July 1768 contained in the Letterbook carried on the Endeavour, included Additional Instructions authorising James Cook to take possession of ‘a Continent or Land of great extent’ thought to exist in southern latitudes and instructed him ‘with the Consent of the Natives to take possession of Convenient Situations in the Country in the Name of the King of Great Britain’.  These provided that, if he found the Continent, he should chart its coasts, obtain information about its people, cultivate their friendship and alliance and annex any convenient trading posts in the King’s name. Cook followed the coast of New Zealand showing that Abel Tasman had been wrong to conclude that it formed part of the southern continent and then turned west, reaching the southern coast of NSW on 20 April 1770. He sailed north, landing at Botany Bay one week later, before continuing to chart the Australian coast all the way north to the tip of Queensland. There, on Possession Island, just before sunset on 22 August 1770, he declared the coast a British possession
Notwithstand[ing] I had in the Name of His Majesty taken possession of several places upon this coast, I now once more hoisted English Coulers and in the Name of His Majesty King George the Third took possession of the whole Eastern Coast . . . by the name New South Wales, together with all the Bays, Harbours Rivers and Islands situate upon the said coast, after which we fired three Volleys of small Arms which were Answerd by the like number from the Ship.
Cook had recorded signs that the coast was inhabited during the voyage north noting as he returned to the ship the large number of fires on all the land and islands about them, ‘a certain sign they are Inhabited’. Cook then sailed through Torres Strait, returning to England in May 1771. Cook’s Secret Instructions represented the first official expressions of British interest in Australia combining the pursuit of scientific discovery with the desire to find exploitable natural resources and to expand Britain’s control of strategic trading posts around the globe and assumed that these varied interests could be made compatible with a respect for the native populations in those countries. Cook’s observations along the NSW coastline on his first voyage formed the foundation for Britain’s decision to establish the colony at Botany Bay in 1788.
Cook’s second and third voyages involved a fuller exploration of the Pacific and Atlantic, including the search for a north-west passage through the Pacific to the Atlantic. He was instructed to make scientific observations and collect natural specimens, and to show ‘every kind of civility and regard’ to the natives, at the same time taking care not ‘to be surprized by them’. With their consent, he was to take possession in the name of the King of any convenient situations in any country he might discover. Cook eventually reached the north-west passage, but the Bering Strait was ice-bound and he was unable to cross it. Returning through the South Pacific, he was killed in the Sandwich Islands on 14 February 1779.
John Cleveley, Death of Captain Cook, aquatint, 1781
 Beaglehole, J.C., The Life of Captain James Cook, (Stanford University Press), 1974 and his editions of Cook’s journals, The Journals of Captain James Cook: The Voyage of the Endeavour,1768-1771, (Cambridge University Press), 1955, The Journals of Captain James Cook: The Voyage of the Resolution and Adventure, 1772-1775, (Cambridge University Press), 1961 and The Journals of Captain James Cook: The Voyage of the Resolution and Discovery, 1776-1780, 2 Vols. (Cambridge University Press), 1967 are the standard works. Edwards, Philip, (ed.), James Cook: The Journals, (Penguin Books), 2003 is an abridged version.
 This Letterbook contains the only surviving set of Cook’s original Secret Instructions. See, HRNSW, Vol. 1, (1), pp. 398-402 for the secret instructions for Cook’s third voyage.
 Ibid, Edwards, Philip, (ed.), James Cook: The Journals, pp. 120-121.
 Ibid, Edwards, Philip, (ed.), James Cook: The Journals, pp. 122-123.
 Ibid, Edwards, Philip, (ed.), James Cook: The Journals, pp. 170-171.
 Unlike Cook’s interaction with other peoples in the Pacific and New Zealand, his contacts with the peoples in Australia have been relegated to a footnote in history perhaps because they were so brief. See, Nugent, Maria, Captain Cook Was Here, (Cambridge University Press), 2009 for a detailed examination and critique of Cook’s eight days at Botany Bay in late April-early May 1770 and the original encounter on land between the British explorers and the first Australians that has become one of Australia’s founding legends.
 HRNSW, Vol. 1, (1) contains extracts from Cook’s private log and the log book of the Endeavour. However, the volume is perhaps most valuable for the journals of officers, pp. 175-298.