This is a difficult book to assess; it is not without flaws but I almost gave it 3 stars. One of the puffs on the back cover of this edition praises its 'fluency'. I can't agree; the author's style is idiosyncratic - in several places I had to read sentences two or three times to grasp his meaning. He refers to ships-of-the-line throughout as 'line ships', a contraction that grates; even worse, at one point he refers to frigates, sloops and smaller vessels as 'under-line ships', which sets my teeth on edge. He also refers to frigates as 'destroyers' (253-4), which is a very inaccurate anachronism. I noticed a few other minor factual errors and internal contradictions. The book is under-supplied with maps and plans (and those few are somewhat oddly placed in relation to the text). It is also under-referenced; many interesting statements are left as assertions, without any evidence given; sometimes even direct quotations are not properly attributed.
Mostert's conclusions and interpretations are sometimes questionable, if not impossible to accept. For example, he suggests that the confrontation between Lieutenants Camelford and Peterson at Antigua in 1798 might not have ended fatally if the orders sent to Camelford had been addressed to 'Lord Lieutenant Camelford', rather than to 'Lieutenant Lord Camelford' (240), but this is an absurd impossibility; no one could possibly have addressed Camelford in such a way. Military titles always precede personal titles and in any case the term 'Lord Lieutenant' has an entirely different application. No one cares about matters of correct address now (perhaps rightly) but in the late 18th century they did care, and historians have to be aware of that. In another passage Mostert comments on Nelson's reaction to Sir John Orde's misuse of his frigates off Gibraltar in May 1805; he says that Nelson's remarks on the occasion were generous and 'a measure of his incredulity over such a fault' (463) but to me they read more like rather heavy sarcasm.
The greatest issue however, is that Mostert believes in the 'Great Man' theory of history and takes it rather to extremes. He wants to see the whole war as a personal clash between Nelson and Napoleon, which leads to problems at many levels. Napoleon exercised supreme command from an early date and was a prime mover throughout the period while Nelson was a subordinate commander for much of the time and was dead before the wars were half over. At times the effort to link the two men becomes desperate, as when he notes that Nelson left Cadiz for Gibraltar on 2 May 1798 and Napoleon left Paris for Toulon on the following day and breathlessly tries to turn it into a signifier of providence (251); it isn't even a coincidence.
Napoleon rose from relatively humble origins to be Emperor of France; the greater part of the wars are named after him (it is very rare for any war to be named after an individual); it is not difficult to cast him as a 'Great Man' or, if you prefer, a 'Bloody Nuisance', given that he caused the deaths of tens of thousands and misery to millions by his insane rampages across Europe, north Africa and Asia. But even Napoleon was not infallible, after all; his dismissive comments on the difficulties faced by his admirals (460) are idiotic, even for a landlubber. I have no desire to denigrate Lord Nelson who I have long admired, but I don't think that the sort of hagiography that Mostert attempts here does him any favours. Even Mostert is forced to deal with his occasional silliness and vanity; his tactical and strategic errors; his vindictiveness; the contradictory, and often very bad, advice that he gave to others.
The trouble with the 'Great Man' approach is that it takes insufficient account of luck, a major and usually under-acknowledged factor in all our lives, and that it tends to diminish the contributions of everyone else. (On the topic of luck, it is of some interest to reflect that Napoleon went through the whole of these wars, taking part in most of its major land battles, without apparently getting scratched, while Nelson got bits shot off him almost every time he went into action.) It is irritating to read over and over again that 'only Nelson' could have been placed in command or achieved such-and-such a success (e.g. 437, 448, 518-20); the Royal Navy of this period had its share of incompetents but it also boasted a great many highly capable officers - Keith, Cornwallis, Saumarez, Duckworth or Collingwood (the only one that Mostert will admit), to name but a few. The accusation that Anthony Hunt 'made minimal contribution' to Nelson's success at Bastia could bear further research, rather than just taking Nelson's word for it, as Mostert is happy to do (129).
Having said all that, Mostert is clearly a knowledgeable individual and the book includes much material that I have not come across elsewhere. It is particularly strong on the North American situation and topics such as neutrality.