I've recently been working on a perturbation theory course in my school, but to say the least, it has been entirely disappointing. I had originally taken it to try to learn more about the three-body problem, but no one I've asked (the professor included) seems to know much about it (and I haven't seen any actual applications of any sort at all).
For this post in particular, I'm very curious about a restricted version, with the Earth-Sun-Moon system. My understanding from Wikipedia is that Perturbation theory was developed in order to understand how the three objects interact. However, asking around the department and searching on Google has not lead me to any discussion on this computation (either original or modern). I was wondering if any of you had any resources that could send me in this direction. Books or internet sources would be fine!
Thanks everyone for your time.