The Selfish Gene & The Blind Watchmaker by Dawkins

Evolution is the reason we exist! Understanding how it happens and why it can lead to counterintuitive outcomes is very important. He also narrates his own audiobooks and is excellent at it.

The Blank Slate & The Better Angels of our Nature by Pinker

Both books counter much accepted wisdom. The second book, in particular, will make you think of humanity in a fundamentally different light.

The Black Swan & Fooled by Randomness by Taleb

The role of chance in everyday life! It plays a big role!