treatise

noun

1. A formal, usually lengthy, systematic discourse on some subject.

   “"As you cannot make a speech, you must," said Henrietta, "put it into a treatise."”

   ““[…] We are engaged in a great work, a treatise on our river fortifications, perhaps ? But since when did army officers afford the luxury of amanuenses in this simple republic ?[…]””

   “And if someone wants to know how to make objections to actual craftsmen themselves on the subject of art in general or any particular art, there are published treatises available, as you know.”

   “Some poems, echoing the purpose of early poetic treatises on scientific principles, attempt to elucidate the mathematical concepts that underlie prime numbers. Others play with primes’ cultural associations. Still others derive their structure from mathematical patterns involving primes.”