I used to link to book titles on Amazon. Several months ago, chastened by criticism I received from supporters of local bookstores, I stopped the links.
While I agree that it’s important to support independent booksellers, I’m going to revive the links to Amazon in deference to requests from readers.
Where you buy the books I mention is up to you. Powell’s and Abe Books are good online alternatives. Mostly I shop at The Strand or St. Mark’s. Occasionally I buy from–the horror!–Barnes & Noble online, because the site offers free next-day delivery in Manhattan.