Her book _The Virtue of Selfishness_ is the primer interested folks should read first to get a handle on her philosophy of Objectivism and to unlock the proper point-of-view while reading her novels. _The Ayn Rand Lexicon_ is also a great book for learning the why for opinion on a lot of topics. Both books spell out her work pretty plainly and she doesn’t talk down to you nor dive into philosophical wonk-speak to explain herself.
The Ayn Rand Lexicon is one of my bookmarks. I pick out a different subject everyday to read.
During the Trump campaign, I re-read some of those books and it's eerie how the Democrats are resembling the "looters" that she warned us about all those years ago. In fact, some of the Democrats like Chuck Schumer and that newcomer Ocasio-Cortez seem like they are right off the pages of "Atlas Shrugged" (as the looters).
"The Virtue of Selfishness" was an interesting read as well as an interesting title. My wife spotted that book on my nightstand and immediately jumped to conclusions.
Rand redefined "selfishness" for me. Selfishness is not me wanting to keep for myself what I have earned. To me, selfishness is others wanting (even demanding) what I earned. Those are the selfish people.
As for her staunch atheism - I can look past that.