Marcio Jose Sanchez/AP; Elisa Glass/The Atlantic

The Earl of Chesterfield, the 18th-century British statesman and patron of the arts, had a number of concerns about his illegitimate son Philip, but one he revisited often in his posthumously published letters to the boy is about Philip’s correspondence. This species of worry ranged from handwriting (“shamefully bad and illiberal; it is neither the hand of a man of business, nor of a gentleman, but of a truant school boy”) to the boy’s prose style (“one principal topic of our conversation will be, not only the purity but the elegance of the English language; in both which you are very deficient”).

The latter became a particular concern after Chesterfield went to the trouble of setting the boy up in the world. In December 1751, he offered Philip some delightfully modern-sounding advice on his business correspondence:

The first thing necessary in writing letters of business, is extreme clearness and perspicuity; every paragraph should be so clear and unambiguous, that the dullest fellow in the world may not be able to mistake it, nor obliged to read it twice in order to understand it. This necessary clearness implies a correctness, without excluding an elegance of style. Tropes, figures, antitheses, epigrams, etc., would be as misplaced and as impertinent in letters of business, as they are sometimes (if judiciously used) proper and pleasing in familiar letters, upon common and trite subjects. In business, an elegant simplicity, the result of care, not of labor, is required.

In case Philip might mistake his meaning, and perhaps reasoning that a demonstration of his recommended prose style was worth much more than a mere description of it, His Lordship added, “Let your first attention be to clearness, and read every paragraph after you have written it, in the critical view of discovering whether it is possible that any one man can mistake the true sense of it: and correct it accordingly.”

Lord Chesterfield’s advice on business writing, published in 1781, joined a heap of careful and voluminous 17th- and 18th-century attention to business correspondence. Titles such as The Young Secretary’s Guide, Or A Speedy Help To Learning; The Complete Art of Writing Letters; and Every Man His Own Letter-Writer were immensely popular bestsellers; The Young Secretary’s Guide went through more than 20 printings and piratings, from 1703 well into the 1750s. And if imitation is the highest form of flattery, we can gauge something of the book’s status in the fact that in 1730, someone got the bright idea to call his version The Young Secretary’s Guide Compleated: Being the Speediest Help to Learning. (This time, with 57 percent more learning.)

The format of the manuals, which were large collections of letters between imaginary but archetypal characters, also lent itself to recycling. An introductory letter to the reader would always lay out the general principles of entering into correspondence and the purpose of the manual: As the century went on and these manuals acquired ever increasing numbers of imitators, some of them would use this opportunity to explain, eloquently, the necessity of another entrant into the lists. Although we must allow for a certain natural exaggeration in what essentially amounted to a sales pitch or the 18th-century version of jacket copy, it’s from these introductory notes that we get a sense of the great regard in which business correspondence, and letter-writing generally, was held. From Every Man His Own Letter-Writer, for instance, we learn that “the importance and necessity of letter-writing, as it relates to our social and commercial concerns in every rank and station in life, are so evidently apparent, as to stand universally confessed…it becomes the duty and interest of each individual member of the community, to acquire a competent knowledge in an art which equally redounds to their credit and advantage.”

After this self-justification would follow a table of contents of each kind of letter contained within the book: a clear necessity, as the manuals represent just about every possible situation one can imagine occurring under the conditions of early British capitalism. Sample letter titles: “From a Shopkeeper in the Country to a Tradesman in London, Complaining of the Badness of his Goods” and “From one Friend to Another, generously offering him Assistance, on his having sustained great Losses by the Failure of a Correspondent” and the perennially popular “From a Guardian to His Ward, against a volatile, frothy French lover.”

As the genre—like Chesterfield’s letters to his prodigal son—was ostensibly directed at the young and naïve, almost every example of it follows a natural progression, from children writing to their parents thanking them for placing them in apprenticeships, or (in the case of daughters) in service, to masters writing up apprenticeship contacts once they had completed their own apprenticeships and acquitted themselves with enough linguistic propriety to advance in the world of business. Some later manuals tend to follow the same characters, from errant apprentices writing to their fathers for more pocket money, to young men writing to prospective father-in-laws to ask for their dowries and daughters, to older men writing to excuse their debts or requesting that debts to them be paid. The ubiquity of letters about every possible permutation of debt is especially prone to the creation of characters, whom you can follow through initial requests to successful (or unsuccessful) petitions to their creditors, and their creditors’ replies.