Help me find an old programming book(s)

Hi!
I recently watched that video by a reddit co-founder Alex Ohanian where they announce reddit is open-source
There a re 4 books in the background:

1. Programming Python - O'Reilly Media

2. Beautiful Code - O'Reilly Media

3. Learning GNU Emacs - O'Reilly Media

4. Unknown

I am sure about number one and three, a bit less sure about number 2 and have no idea about 4 except that it's about the Erlang language