Book "Gems" for SMP

It would be useful, in my opinion, to have a general list of books that many here would consider 'Gems'. In this I mean books that deal with science, math, or philosophy that can inspire, explain, and otherwise be interesting and worthwhile to not just specialists but any intelligent layman. Of these, I am not just referring to books that popularize a particular subject but others also that tend to explore new things in themselves. Of course this is not to downplay such gems as say, A Brief History of Time.

To start the universe from nothing, I will mention a few books as much for example as to begin to populate the void:

Relativity The Special and the General Theory, by Albert Einstein

A Mathematician’s Apology, by G. H. Hardy

The Story of Philosophy, by Will Durant

What is Life? by Erwin Schrödinger (this real gem of a book has an epilogue titled 'Determinism and Free Will' which is a wonderful Ferris wheel ride of thought).

If others take this seriously and add to it, I suppose it may be worthy of being a sticky. But that will depend on how this thread evolves.

I encourge all to participate and add their own suggestions of 'Gems'.

-Zeno