The choice is very limited. Among books written for a popular audience, there's nothing at all worth mentioning (I'm not counting E. M. Forster's awful book on Alexandria, or books solely about the Mouseion). In a more academic genre, the selection will depend on what you're after, so here are, I think, the main highlights:
P. M. Fraser (1972), Ptolemaic Alexandria, 3 vols., Oxford. -- large (3 volumes), very thorough documentation, very academic. Focuses on the 1st century CE.
Christopher Haas (1997), Alexandria in Late Antiquity, Johns Hopkins Univ. Press. -- covers ca. 300 CE to 500 CE, plus extra bits at both ends.
Günther Hölbl (2000), A History of the Ptolemaic Empire, Routledge. -- Ptolemaic, not specifically Alexandrian, history; covers 323 BCE to 30 BCE.
W. V. Harris and G. Ruffini, eds. (2004), Ancient Alexandria between Egypt and Greece, Brill. -- a collection of academic essays on various topics: demography, Ptolemaic propaganda, intellectual history (incl. art, literature, medicine), papyrology, and ethnicity.