Know Your Next Word : epistolary
4. epistolary :
1. Of or relating to letters
2. Composed of letters (as a literary work)
Case in point : Griffin & Sabine, Nick Bantock's epistolary novels told entirely through extravagantly illustrated postcards and letters tucked into envelopes contained in the book.
Jennie Yabroff : Love on the Blocks : Newsweek (New York) : Mar 2 - 2009.
an epistolary friendship
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