on the "Pawpeds"-website - wellknown for the database where we can see and research and testmate pedigrees of over 16000 Maine Coons from the very first registered ones on - you can research through a quite big section which is beholden to our breeds history, collecting articles, interviews, cattery presentations :
So we can find a section on the Maine Coon Ancestors - including the Methusalem-list of breeding cats who got over 15 year old : https://www.pawpeds.com/MCO/ancestors/ ,
and a section where you find a collection of all the interesting historical informations on our breed, the
Maine Coon Heritage Site: https://www.pawpeds.com/MCO/mchs/
Interesting also, and highly recommendable is the course system, that pawpeds offers to fanciers and especially breeders of cats: https://www.pawpeds.com/pawacademy/courses/
Also on the MCBFA website we can find a huge archive of historical lore on our Breed, all the "Scratch Sheets", the members newsletter & Magazine from the foundation of MCBFA prior to the acknowlegdement of the breed in the various associations until its last issue in 2013 : this might be a most fascinating read, lots of information on breed, breders, catteries, health, show-wins and also some trivia you will have never imagined: http://www.mcbfa.org/coonmaine.html
for the geneticist I found a rather interesting site about the genetic diversity of the Maine Coon - check it out.:
https://www.catterymacadamia.com/amp/genetic-diversity-of-the-maine-coon