Whether by chance, or in consequence of all his matrimonial prayers having finally been answered, once Constable and Maria were happily united - and began to be surrounded by one of those alarmingly unrelenting precontraceptive families (Maria had eight pregnancies in double-quick time) - his professional good fortune began to match his private felicity. At this point, Gayford's self-imposed task is all but done: they marry on page 318 and a mere 18 pages suffice to round things off.

It is revealing to contrast this division with that encountered in the still tremendously readable and affecting Memoirs of the Life of John Constable (which quotes extensively from its subject's writings and correspondence), by the artist's friend, C.R. Leslie, published in 1843, where, in the copy I own, they marry on page 69 of 331. Poignantly, John and Maria were granted only a dozen years together. Three days after her death from consumption, Constable wrote: "I shall never feel again as I have felt. The face of the world is totally changed to me."

One has no sense that the long years of separation and suffering before his marriage were the making of Constable, but this book could not have been written without them, since it relies so heavily on the couple's correspondence both to one another and - in the case of Constable - to family and friends. Emails and texts, and indeed the phone even before it achieved mobility, have made it impossible to conceive of anyone writing any such intimate biography of a 20th- or 21st-century subject in his or her own words.