Epistolary Novel অনেকটা চিঠির মতো করে লেখা এই উপন্যাসগুলো। - A novel told through in the form of letters. - The narrative of this type of novel is carried forward by letters written by one or more of the characters of that novel.
Example: Pamela by Richardson.
Source: An ABC of English Literature - Dr M Mofizar Rahman