Books written primarily/entirely in messages or letters

[Kety]

I recently read Technically, You Started It and I enjoyed it. I was looking for something similar. I want something where a strong relationship develops between two characters - not necessarily romantic, it can be completely platonic or even hateful but just something with character dynamics. I want it to be between people (so not like The Perks of Being a Wallflower). Preferably contemporary YA or NA. Thanks in advance!

[Emily]

This thread might be helpful:
Epistolary novel

[Beverly]

The Screwtape Letters
Daddy-Long-Legs

[Gillian]

Ella Minnow Pea: A Novel in Letters by Mark Dunn and Dracula by Bram Stoker.

[Nora]

One of my all-time favorites is The Guernsey Literary and Potato Peel Pie Society.

[...cats?]

The Year of Secret Assignments by Jaclyn Moriarty
P.S. Longer Letter Later and Snail Mail No More by Paula Danziger and Ann M. Martin
Gena/Finn by Hannah Moskowitz and Kat Helgeson

[Helena]

I think you might like Pale Fire. It's not exactly letters but one man writes a poem and the other obsessively comments on it, so it might fit your interests. The relationship between these two men is fascinating and I consider this book one of the greatest of all time.

[Evren]

Ella Minnow Pea: A Novel in Letters -by Mark Dunn
Love Letters to the Dead -by Ava Dellaira

[Caroline]

Address Unknown
A short read, not many pages, but with great impact.