Although this edition of Cook's 'Journals' shows evidence of various levels of later tweaking and revision by Cook, it nevertheless retains a very vivid sense of all the practical and logistical difficulties that he faced in his three great voyages, to the extent that you can almost put yourself back into the situation that faced him at the start of his explorations when the South Pacific, Australia and New Zealand were virtually blanks on the map except for a few unconnected and largely forgotten landfalls by Tasman and others long before. Even when you know that he survived, it can be quite gripping when Cook is fighting his way around Cape Horn or picking an infinitely careful route through the Great Barrier Reef, and very nearly coming to grief in the process.
Cook's journals make plain what we find too easy to forget, how the business of exploring and charting unknown and often hazardous coasts was hampered by the limitations of working a sailing ship against prevailing winds, by a huge range of practical issues like finding fresh water and suitable food to keep scurvy at bay, and by unending problems of what we'd now call 'human resources' management - which in Cook's case included potentially hostile native peoples, drunken and unruly sailors and marines, and his accompanying band of aristocratic and self-important scientists. Cook often seems a dry and understated professional, but he occasionally shows flashes of what seems quite a modern sense of humour: 'he being one of those gentlemen, frequently found on board Kings Ships, that can very well be spared, or to speake more planer good for nothing'.
I found that having read the 'raw material' as it were, I at once wanted to go on to find more commentary and analysis to fill in the background to these extraordinary voyages. But this remains the basic source, and it's very useful to have it available in such an inexpensive and unobtrusively edited format.