Larry McMurtry lived in the Bay Area in the 1960s, and he recounts in his memoir, entitled Books, his visit to Bell’s Books:
“The famously grouchy Mr. Bell in Palo Alto ordered me off his second fl0or, although I had a book in my hand and I bought it!” (page 50)
(During that decade the second floor was frequently roped off for book processing.) Today, you are free to browse that area, which includes history, philosophy, sexuality, religion, psychology, translated fiction, genre fiction (mysteries, science fiction, horror), and nature.