treatise

n. formal systematic treatment of a particular subject, essay, dissertation

A treatise is a formal, usually lengthy, systematic discourse on some subject.
See more at Wikipedia.org...

Noun
1. a formal exposition
(hypernym) writing, written material, piece of writing
(hyponym) dissertation, thesis

(n.)
Story; discourse.
  

(n.)
A written composition on a particular subject, in which its principles are discussed or explained; a tract.
  

    treaties    iterates