In Fahrenheit 451, why do the hobos identify themselves as famous authors or pieces of literature?
The hobos that Montag meets are modern-day Homers, memorizing books to pass their knowledge along as a new oral tradition. They each memorize books in their entirety, using mental techniques to close those memories off until they are needed; this prevents forgetfulness and degradation of memory. When Montag meets them, they introduce themselves in literary terms:
"I want you to meet Jonathan Swift, the author of that evil political book, Gulliver's Travels! And this other fellow is Charles Darwin, and-this one is Schopenhauer, and this one is Einstein, and this one here at my elbow is Mr. Albert Schweitzer, a very kind philosopher indeed. Here we all are, Montag. Aristophanes and Mahatma Gandhi and Gautama Buddha and Confucius..."
(Bradbury, Fahrenheit 451, Google Books)
This odd method of identification allows the men to quickly know who has memorized what, so as to avoid unnecessary duplication. While some duplication is necessary, in case of sudden death, too much is redundant. Another reason is to keep their real names hidden; while the book-burners might recognize the names, others will not, and so they can travel in anonymity by using their literary pseudonyms. Finally, it allows classification along philosophical and genre lines; a person who specializes in political writing will leave religion to others, which a science expert will avoid science-fiction, so as not to get confused.