But Adams did not just read books. He battled them. The casual presumption that there is some kind of rough correlation between the books in the library of any prominent historical figure and the person’s cast of mind would encounter catastrophe with Adams, because he tended to buy and read book with which he profoundly disagreed. Then, as he read, he recorded in the margins and at the bottom of the pages his usually hostile opinions of the arguments and authors.... [T]he Adams marginalia constitute evidence more revealing of his convictions about political theory than any of his official publications.
Heyward Jr., Thomas
Passionate Sage: The Character and Legacy of John Adams (1993)