Constance, or Solitary Practices is the central volume of the five novels of Lawrence Durrell's The Avignon Quintet, published from 1974 to 1985.

It is at this point in the book that Durrell begins to introduce 'fictional' characters from Monsieur, the first in the quintent, including its author, the novelist Robin Sutcliffe, himself a fictional invention of Blanford's.

Alongside this, a number of characters from The Alexandria Quartet make 'cameo' appearances, including British Ambassador David Mountolive, intelligence officer Maskelyne, the gnostic Balthazar, the novelist Pursewarden and the dancer Melissa, who sleeps with Sebastian Affad and is rewarded with three cigars to gift her Jewish patron and lover.

American critic John Leonard, writing for The New York Times, was highly critical of Durrell's work in this novel and the previous two books of the Quintet so far: "For a novelist like Mr. Durrell, almost any idea is incapacitating, an excuse to abandon his lyric impulse and resort to old, lazy tricks, like one writer talking to another or confiding in his notebook or finding fragments of a third writer's diary.

Memory - 'a dog on your back gnawing at your eyeballs' - is Mr. Durrell's real subject, but so far, sad to report, Proust has nothing to worry about.