@Brandon9000,
Well, first of all Brandon9000, I don't rely on secondary sources or materials for information about the Beatles, but rather I go straight to the primary sources, which is the music itself, as a research material. And secondly, none of those types of books that you allude to contain anything in which I am really interested. What have you learned from them that bears directly on the topic in question? I venture to say absolutely nothing but subjective opinion and hearsay.
The only thing that really matters is the music, and it is the music itself that gives us the unequivocal objective information that Lennon and McCartney could not possibly have authored the Beatles' 1962-1970 due to the incontrovertible evidence pointing exactly to the contrary, namely, that the stylistic and structural characteristics of the extant compositions known to have been written by Lennon and McCartney from before 1962 and from after 1970, during the periods when Lennon and McCartney were not professionally associated with George Martin, is mutually exclusive or categorically incompatible with the stylistic and structural characteristics present in the Beatles' song hits from 1962-1970. This information points directly to George Martin as being the sole author of these 1962-1970 hit songs, which are the only songs on the basis of which George Martin and the Beatles under him were forever catapulted to instantaneous and unprecedented fame and fortune.
As to the topic that should really concern us - Lennon vs. McCartney: Who was the least creative composer of this duo? Definitely Paul, as the least competent of two comparatively incompetent and mediocre songwriters.