Consulting newly available primary sources, evaluating the biographers that have come before him, devoting a massive first volume (Henry Holt, 960 pages, $35) to Nelson’s early career (somewhat neglected, he believes), John Sugden is clearly aiming at establishing the definitive life of Nelson. To any scholar of Nelson, this book is indispensable, but for the reader of biography … well, that is another matter.

Mr. Sugden writes reasonably well (although he could handle pronouns better) in his quest to portray “the whole man.” Commenting on accounts that show Nelson as at once silly and vain and a man of superior sense and professionalism, the biographer observes, “They were both driven by Nelson’s need for distinction and acclaim. It spurred him to extreme endeavor, and to theatrical vanity.”

Then there is Mr. Sugden’s fresh look at the British navy. In the popular mind, it was a rather brutal school for the likes of the frail, scrawny 12-year-old Nelson. Dr. Johnson recommended prison over a tour of duty in the Royal Navy, pointing out that the company would be better and one did not hazard the danger of drowning. Nelson’s naval uncle, Captain Suckling, contributed his own harrowing, if jocular, warning about what his nephew was in for: “What has poor Horatio done, who is so weak, that he, above all the rest, should be sent to rough it out at sea? But let him come, and the first time we go into action, a cannon-ball may knock off his head and provide for him at once.”

Mr. Sugden does not doubt the hard duty aboard ship, but he points out that young Nelson was not enlisting in the “merciless institution of popular folklore.” Rather, the Royal Navy made “many efforts to care for its own. Young Nelson had nothing but good to say of most of his commanders and companions.” Nelson’s justly admired humanity when it came to leading men into harm’s way becomes, in this comprehensive biography, an attribute not merely of the man but of a way of life. Glory was not just a matter of personal ambition but also the achievement of a hero whose identity was inseparable from his nation’s.

I could go on praising a biography that is “not without considerable merit” – a phrase Mr. Sugden applies in grudging fashion to Edgar Vincent’s “Nelson: Love & Fame” (Yale University Press, 640 pages, $35) – except that I cannot get beyond what another reader said to me about this book: “I think you will find Sugden as strange as I have. He will list every odd detail of the written record, but not speculate on what Nelson might have learned on his voyage on an Indiaman as a 12-year-old or as the coxswain to the polar explorer Phipps. I found it dissatisfying after 200 pages, but still very interesting.”

The polar expedition has been a favorite of biographers who want to find in the callow teenager the brash heroics of the admiral. Here is Robert Southey’s grand recounting:

One night, during the mid-watch, he stole from the ship with one of his comrades, taking advantage of a rising fog, and set out over the ice in pursuit of a bear. The fog thickened, and Captain Lutwidge and his officers became exceedingly alarmed for their safety. Between three and four in the morning the weather cleared, and the two adventurers were seen, at a considerable distance from the ship, attacking a huge bear. The signal for them to return was immediately made; Nelson’s comrade called upon him to obey it, but in vain; his musket had flashed in the pan; their ammunition was expended; and a chasm in the ice, which divided him from the bear, probably preserved his life. “Never mind,” he cried; “do but let me get a blow at this devil with the butt-end of my musket, and we shall have him.” Captain Lutwidge, however, seeing his danger, fired a gun, which had the desired effect of frightening the beast; and the boy then returned, somewhat afraid of the consequences of his trespass. The captain reprimanded him sternly for conduct so unworthy of the office which he filled, and desired to know what motive he could have for hunting a bear. “Sir,” said he, pouting his lip, as he was wont to do when agitated, “I wished to kill the bear, that I might carry the skin to my father.”

This scene is suspect, of course – a good story but dubious precisely because it is told with the circumstantiality and dialogue of a novel. Yet Southey, errors and all, remains an important biographer because “his beautifully economic prose cemented the admiral’s status as the authentic British hero,” Mr. Sugden concludes. Or as Carola Oman, whom Mr. Sugden acknowledges as one of the greatest of Nelson’s biographers, puts it: Southey’s “Nelson” is “one of the tales that hold children from play and old men from the chimney corner.”

For all his vaunted reliance on primary sources – new and old – I have my doubts that Mr. Sugden has surpassed Ms. Oman as a biographer. Whereas Mr. Sugden spends 13 pages on the polar expedition, Ms. Oman allots it four. Mr. Sugden has more facts at hand, and is eager to show how wrong other biographers have got it, but he cannot better Ms. Oman’s more memorable retelling of the story or her wry disposal of its merits: “In after years Admiral Lutwidge told his bear story with good humour, and Lord Nelson’s brother-in-law entered it in a privately printed memoir, designed to amuse nieces and nephews of the hero.”

Similarly, while Mr. Sugden is willing to doff his hat (an inch or so) to Mr. Vincent, the chapeau is quickly clapped down with the comment that his competitor “exemplifies the excessive reliance upon familiar published sources, most of which are now more than one and a half centuries old.” Have you noticed that certain biographers tend to be hardest on the contenders that are nearest to hand?

Like Ms. Oman, Mr. Vincent is a wonderful writer. Unlike Mr. Sugden, he is not chary of examining his subject’s psychology:

Much of Nelson’s behaviour suggests a hidden well of insecurity stemming from his childhood. He was a middle child in a large family. He lost his mother when he was nine. His family life was dislocated by boarding-school. He was totally separated from his family at the age of twelve and a half. Thus his unconscious and unacknowledged motivations were a lifelong search for love and for attention, and a need to prove himself over and over again. At the age of eighteen he invented a conscious purpose for his life which fitted his motivations. He decided to be a hero.

Do you like your biographer to act with more restraint? Here is Mr. Sugden, refusing to go beyond the record:

Why Nelson needed this public acclaim no one can say now. Psychologists might probe his childhood, and ponder the mark those lonely Norfolk years made upon a boy who lost his mother before he was ten and whose father spent long months from home; perhaps also the transition into adolescence and manhood spent at sea in a man’s world of hard work and danger. It is entirely possible that Horatio’s lifelong need for attention and affection was in some way rooted in that turbulent and deficient upbringing, but while these speculations must trouble the novelist, historians are unable to enlarge upon them. What we do know is that from an early age Nelson fought for every scrap of glory he could get, and fiercely resented any denial of his just desserts.

For me, the most telling word in Mr. Sugden’s paragraph is “historians.” Biography may contain history, but it is not history; it is something both more and less than history. Wasn’t it Mr. Sugden who said he was after the whole man? To capture him, the biographer takes risks, extrapolating sometimes beyond historical evidence. This is precisely why certain historians do not like biography.

The other telling word in Mr. Sugden’s paragraph is “now.” That simple word cuts him off from biography in its fullest sense, because there was never a “then” when someone – even Nelson himself – could have explained why he so obsessively sought public acclaim. Only biography – that is, the book that becomes a biography – can reconceive a life and attempt to show why no one – not even the biographical subject – can vouchsafe to the reader the purport of his actions. Of course, biography fails. Who among us will concede all the ground to the biographer and say, “Well, that is Nelson, and there’s an end of it.” Yet that is, paradoxically, what readers want and what they sometimes think they get when they call a biography “definitive.”

In contrast to Mr. Sugden, Mr. Vincent plugs for his Nelson by building up a powerful image of an addictive personality: “His need for attention became an addiction … His thirst for love was equally great … When he lay dying, ‘Kiss me Hardy’ was the ultimate softener of a hard man … Battle became another addiction.” This is biography that finds a language to knit together the actions and character of its subject.

Mr. Vincent observed that “to do a subject proper biographic justice requires empathy, and a forensic attitude.” The biographer cannot stand aside; he must submit the subject to the laboratory of his own imagination.