It was a novel.
Rand wrote several novels attempting to illustrate her philosophy, but she wrote dozens of non-fiction books as well as hundreds of essays in which she explained her thoughts in more specific terms.
Now, of course, she remained an atheist and I understand the resistance to her here for that. But even a thorough reading of "Atlas Shrugged" is not enough to understand what the woman was saying.
Her writings were deeply influential in my thinking. She was brilliant. She also allowed her personal beliefs to cloud her thinking [her beliefs on abortion, for example, can't be supported by her own philosophy in my opinion] and her life was chaotic. In short, she was quite human.
But you don't have to be a convert to Objectivism to gain some wisdom from her writing.
However, that is also true of her philosophy. Just as many Christians have a problem separating individual charity from collective exploitism, Rand did as well, or more likely didn't consider the difference worth exploring.
She made a lot of enemies unnecessarily and wound up alienating as much as educating with Atlas Shrugged. She needed more subtlety and refinement to her philosophy and how she presented it.