For almost 30 years, from 1739 to 1768, Philip Dormer Stanhope, 4th Earl of Chesterfield, wrote letters both nagging and magnificent to his illegitimate son Philip Stanhope. These are the letters which Samuel Johnson, no friend to the earl, described as inculcating “the manners of a dancing master and the morals of a whore.” Johnson, of course, nursed a grudge: The earl had neglected to provide him support during his colossal dictionary project, appearing as a patron only when the work had been concluded. For this, Johnson in a famous letter defined a patron as one who “looks with unconcern on a man struggling for life in the water, and when he has reached ground, encumbers him with help.” (To Chesterfield’s credit, it must be said, he was so proud of Johnson’s indignant letter that he left it on a table where his guests might see it.)

I’ve been reading the lord’s correspondence with his son and others, in the convenient selection in the “World’s Classics” series, edited with a fine introduction by David Roberts (“Lord Chesterfield’s Letters,” Oxford University Press, 480 pages, $15.95). They are mesmerizing for the glimpse they give of unbuttoned life in aristocratic English society as well as for their pithiness and genuine douceur (one of the ardent Francophile Chesterfield’s favorite words, meaning “gentleness”).

In this week of Father’s Day, Lord Chesterfield may at first appear to have been the Dad from Hell. His advice to his son is all-intrusive. Worse, the admonitions, injunctions, scoldings, and shrewd counsel were abetted by the reports of myriad informers scattered not only throughout England but all over the Continent; these friends and associates reported regularly on the son’s lapses and faux pas.

In an early letter, Chesterfield remarks, “a man without attention is not fit to live in the world.” He then proceeds to illustrate the disasters that come from inattention: “When an awkward fellow first comes into a room, it is highly probable that his sword gets between his legs, and throws him down, or makes him stumble, at least; when he has recovered this accident, he goes and places himself in the very place of the room where he should not; there he soon lets his hat fall down, and, in taking it up again, throws down his cane. … If he drinks tea or coffee, he certainly scalds his mouth, and lets either the cup or the saucer fall, and spills either the tea or the coffee in his breeches.”

Dinner for the inattentive presages catastrophe. “If he is to carve, he can never hit the joint; but, in his vain efforts to cut through the bone, scatters the sauce in everybody’s face. He generally daubs himself with soup and grease. … Besides all this, he has strange tricks and gestures; such as snuffing up his nose, making faces, putting his fingers in his nose, or blowing it and looking afterwards in his handkerchief, so as to make the company sick.”

Inattention, for Chesterfield, was a profound flaw and the one from which all others proceeded. “Want of thought,” as he put it, “is either folly or madness.”Why? Because success in the world depends upon quick and meticulous observation. Chesterfield didn’t write his letters to his son for publication or posterity; he meant them to be precise directions on how to succeed in life. He himself, though the eldest son, had been disinherited, and he knew that his own son, through illegitimacy, would have to struggle to make his way to the highest echelons of English society. (When he applied to King George II for a diplomatic post for the young man, the king refused with the remark, “He is a bastard.”)

Chesterfield is the Machiavelli of the drawing room. No detail is too trivial for his attentive eye. From writing a proper business letter (“every paragraph should be so clear, and unambiguous, that the dullest fellow in the world may not be able to mistake it”) to riding, fencing, and dancing, as well as the best way to smile and achieve “countenance,” Chesterfield proffers vivid and specific instructions. No prig, he not only advises but urges his son to take two mistresses simultaneously.

At first glance the letters appal. We try to imagine how the hapless son must have felt when the daily missive thudded on the welcome mat. Chesterfield, for all his lavish advice, did not like his son and avoided meeting him as much as possible. When he announced a visit, he gave ample, if mischievous, notice: “In about three months from this day, we shall probably meet. I look upon that moment as a young woman does upon her bridal night; I expect the greatest pleasure, and yet cannot help fearing some little mixture of pain.” The pain Chesterfield anticipates will arise, not from some lack of affection on his son’s part, but from some dread “inelegancy of diction” in English; worse, “if you do not express yourself elegantly and delicately in French and German … it can only be from an unpardonable inattention to what you most erroneously think a little object.”

At this point Chesterfield makes an observation which shows that his fastidious hectoring rested on reasoned foundations. “Solidity and delicacy of thought must be given us: it cannot be acquired, though it may be improved; but elegancy and delicacy of expression may be acquired by whoever will take the necessary care and pains.”

The more we read the letters the less appalled we are apt to feel. They are certainly not the letters we should write our children; they are formal, didactic, bullying, and coolly elegant, with not a slovenly sentence to be found. At the same time their cumulative effect is one of unwavering solicitude and an unusual depth of devotion. Beautifully written in that supple, clarified, and judicious prose the secret of which, it seems, only the 18th century possessed, they are shot-through with surprising insights on every topic under the sun. Chesterfield’s comments on Milton, Ariosto, and Virgil are as astute and original as his deft analysis of political affairs.

His son predeceased Lord Chesterfield by some five years. By then the indefatigable old man was already speeding advice to his godson. “My dear little boy,” he writes in one letter, “Carefully avoid all affectation either of mind or body.It is a very true and a very trite observation that no Man is ridiculous for being what he really is, but for affecting to be what he is not.” Beyond his wit, polish, and intellect, Chesterfield’s letters have the supreme, if inadvertent,virtue of showing us a man “being what he really is.”