I am looking on getting more in-depth books on the BF 109 does anyone have any suggestions?
i like aircraft encyclopedias they do a lot other than that i dont know sorry mate
This one looks pretty good . . .
Messerschmitt Bf 109 F, G, and K Series: An Illustrated Study Hardcover β September 29, 1992
by Jochen Prien (Author), Peter Rodeike (Author), David Johnston (Translator)
Regarding technical aspects there are way too many good books available, but for combat related insights i recommend the memoirs of Heinz Knoke as described on wikipedia.
Especially his combat reports of his aerial bombings of B-17 combat boxes are imho very unique and canβt be found anywhere else.
I have a Haynes manual of the Stuka and itβs great, really technical and shows an in depth explanation of each part. The manual also has some historical details, but itβs not as thorough as the technical part. So the Bf-109 manual should be of a similar quality. If you can find one on sale it is basically a steal.