First, let me make it clear that I have no personal grudge against Nigel Hamilton. He writes well, and I believe prospective biographers would do well to read his book.
My quarrel is with Hamilton's indifference to the importance of truth, which unconcern he flaunts in his opening chapter by declaring that the biographical "shots heard round the world" were Edmund Gosse's Father and Son (1907) and Freud's Leonardo da Vinci (1910). Likewise, in a later chapter, while defending the salaciousness with which he approached the life of Bill Clinton--a "sleazy new low" repeating "the most scurrilous and unsubstantiated rumors," wrote one critic--Hamilton defends his prurience by citing the comments of Suetonius on the sexual perversion of the Roman emperor Tiberius.
The problem with all three of these examples is that they are at worst, false and at best, not susceptible to proof. Freud's "outing" of Leonardo as a homosexual is based on a phantasmagoria. Even Charles Nicholl, a Leonardo biographer (2004) who believes Freud's speculations are "worth listening to," notes that critics have denounced Freud's work as "highly speculative psychology on top of highly speculative history, and they are right." (33-34) Peter Gay's careful biography of Freud, which Hamilton himself quotes at some length, reveals that Freud himself called his long paper on Leonardo a "halbe Romandichtung," a half-fictional production.
Suetonius's eyebrow-lifting stories of Tiberius molestation of slave boys may well be true; but they are again just as likely false. Suetonius had an ax to grind with Tiberius and perhaps with all emperors. At least the Oxford History of the Classical World (1986) declares that Suetonius's "scandalous descriptions" of the emperor's intimate life make for "an effective, though not necessarily accurate, character portrait." The Oxford Classical Dictionary (1996), even less enamored, says that the "stories of vice...may be discounted." (1523-24)
As for Gosse's beautifully written Father and Son (1907), its portrayal of Philip Henry Gosse as a tyrannical, joyless, religiously maniacal father is literarily and psychologically true but factually bogus, as Ann Thwaite--the biographer of both Gosses--has adequately demonstrated in her fine (and unfortunately almost unknown) Glimpses of the Wonderful: The Life of Philip Henry Gosse (2002). Gosse pere, though deeply religious, turns out to have been a warm and generous person, deeply in love with life and his family, a man who was slugged into opprobrium by his son's memoir.
Hamilton argues that the biographer should "follow, document, and verify the results of genuine, open-minded curiosity." (91-92) But often missing from his examples is his own skeptical questioning. Hamilton draws appropriate negative lessons from the Reagan "biography" of Edmund Morris and the "memoir" of James Frey, but he is loathe to give up the gossip that gives "color to people's lives." (193) I leave him to it, to his conscience and to his prospective royalties.
Although Hamilton claims to know of "no book or primer to guide the would-be biographer," (1) there have been others, the names of some of which are given in his bibliography. (A true "primer," Milton Lomask, The Biographer's Craft [1986] is an obvious omission, but a work mediocre enough that its absence is certainly pardonable.) My own favorite book about biography (also missing from Hamilton's bibliography) is William Zinsser, ed., Extraordinary Lives: The Art and Craft of American Biography (1986), a series of six lectures given at the New York Public Library and tidied up for publication. Read both Hamilton and Zinsser, and see if you don't find the latter both more fun to read and more practical in its direction.