This is a collection of other books not strictly related to operating systems, but discussing topics which undoubtedly affect them.
Knuth, Donald . The Art of Computer Programming, Volume 1. Addison-Wesley, 1997. A priceless tomb of perfection (seriously) in the fundamental algorithms of computer science, including best- and worst-fit algorithms used in memory management.
Hofstadter, Douglas . Gödel, Escher, Bach: An Eternal Golden Braid. Basic Books, 1999. A profound and indispensable look at human thought that delves wildly into multiple subjects, including computer science.