“George III: America’s Last King” (Yale University Press, 448 pages, $35) adds much to our knowledge of the monarch and his reign. I was intrigued to learn about George’s reading and how much writing he produced. He was an earnest, if not very subtle thinker. The word often applied to him is stolid. The biographer’s research is impressive, but I’d recommend that you clear your calendar and wear a pair of noise-canceling headphones whilst (as the Brits say) you attempt to decipher Jeremy Black’s prose.

There is a reason why some biographies are called “academic.” In Chapter 19, “Reputation and Comparisons,” Mr. Black states:

The British monarchy, or the image of the monarchy, was reconstructed during the later years of George’s reign. The strong patriotism of the war with France, and the king’s less conspicuous role in day-to-day politics, combined fruitfully to facilitate the celebration less of the reality and more of the symbol of monarchy. In this, the precondition of the creation of a popular monarchy was (ironically but significantly) the perceived decline in the crown’s political authority in a partisan sense, at least its use thus in a clear and frequent fashion.

When I got as far as “in this,” my eyes began to cross and the question of what to plant in my spring garden suddenly seemed of paramount concern.

Is there any excuse for such writing? Do monarchy wonks thrive on it? The first two sentences quoted above, with their needless repetitions and plethora of prepositions are illustrative of the ponderous locutions that thud throughout this biography. Translation: As soon as George III stopped meddling in everyday politics the monarchy as a symbolic institution began to thrive. By doing less, George actually enhanced the authority of the monarchy, even though it seemed to partisans that he had weakened it. What more needs saying? Did I miss something?

It is with considerable relief that I turned to Stella Tillyard’s “A Royal Affair: George III and His Scandalous Siblings” (Random House, 384 pages, $26.95). The title may suggest that this book is historylite, but not a bit of it. In a delightful introduction, Ms. Tillyard describes how together with her assistant she conducted painstaking research in the Hanoverian archives, plowing through towering piles of metal boxes: “Across the faces of other researchers, as we passed, flitted expressions that mixed polite astonishment with just a hint of disdain.”

In Hanover, the court kept records of everything: When George II had his son inoculated for smallpox in 1724, “His English doctor wrote a daily report on his condition, recording the prince’s mood and temperature and the number of spots on his skin.” I can imagine the comic figure Ms. Tillyard cut among her fellow researchers: Was she really going to sift through all this detritus, and to what end?

Already sympathetic to this scholar dredging through the past, I quickly grasped that a certain level of detail was essential to craft a narrative as compelling and colorful as that of a novel. But this is hardly all that Ms. Tillyard accomplishes. She is writing a group biography with George III at its center, and she shows that his overwhelming sense of responsibility for his siblings — most of whom had nothing much to do — is of a piece with his politics, in which the erring American colonists, for example, had to be brought into line in the same way a father disciplines his children or an older brother reads the riot act to the younguns.

George III took himself very seriously as the father of his nation, the one figure who could rise above factions and self-serving institutions to represent and guide his people. But as one court observer noted, it was all very well if George III was on the side of right, but what if he mistook wrong for right? To whom does one appeal a father’s decisions? Curiously, George III (sometimes accused of being a closet Jacobite!) came near to believing he ruled by divine right.

By describing and assessing how the king dealt with his own family, Ms. Tillyard also makes her contribution to the genre of biography:

Biography tends to be a vertical genre, going from parents to children, explaining its subjects by virtue of their childhoods and their relationships with their mothers and fathers. It rarely dwells for very long on brothers and sisters and the importance they can have in one another’s lives. Perhaps because I am from a large family myself, my work had tended to go the other way, to be horizontal, seeking in the tangled web of brotherly and sisterly relations other clues to what makes us who we are.

Has a biographer ever so elegantly conjoined in a compact paragraph the nature of biography, her research interests, and her own biography with the reader’s interests?

George III had one sister, Caroline Mathilde, who married a mad Danish king and suffered the horrible consequences of an affair with a radical young court doctor. George III’s brothers led scandalous, dissolute lives on the royal dole. And yet he refused to give up on this family, just as he would not relinquish his claim on the American colonies. To do so would strike at the heart of his paternal values.

George III’s father, Prince Frederick, who died in his 30s (making his son George next in line to Frederick’s father, George II), had suffered the neglect of both mother and father and thus decided that the future George III (“a serious boy,” Ms. Tillyard calls him) would know what it meant to have a warm heart and would come to regard loving family relations as the basis for a ruler’s values. Frederick, in fact, left specific instructions for his son, emphasizing: “Tis not out of vanity that I write this; it is out of love to You, and to the public. It is for your good, and for that of my family, and of the good people you are to govern, that I leave this to you.”

To speak of love and family and the nation, combining in such a tender way the personal and the political, surely marks a new development in British history. The monarch as person and symbol fused. But at what cost to George III, Ms. Tillyard shows. The burden of representing and unifying the British world was too much for one man — any man — who could no more keep his empire together than he could make peace among his own family.

crollyson@nysun.com