Epistolatory in a sentence as an adjective

Williams was not an unknown: his epistolatory novel Augustus won a National Book Award. I read Stoner in the late 1970s, before it went out of print for some time.

Epistolatory definitions

adjective

written in the form of or carried on by letters or correspondence; "an endless sequence of epistolary love affairs"; "the epistolatory novel"

See also: epistolary