The Making of the Atomic Bomb
The truly fascinating story of the scientists and military and political leaders who conceived and developed the first atomic bomb. Well written, with great insight into the personalities and feelings of those involved. The science and engineering work are covered fully, but I thought the most interesting parts were the thoughts of the scientists themselves - whether science should aid in developing such weapons, the effects on war and politics in the future, the fears of what could happen if Hitler or Stalin developed a bomb first. Winner of the Pulitzer Prize. The same author also wrote Dark Sun, which is about the H-Bomb and covers a lot more of the spying and communist sympathies held by some of the scientists. If you only have time for one of these, this book is the better of the two.
Another cool shirt for The Large Hadron Collider nerds
The Large Hadron Collider is turned on and looking for A Big Bang
I recommend this book for anyone who thinks Science and Theology can't share the same plate. A look into one of the greatest minds in Physics and his personal conception of a higher power.
If you're looking to time travel, but can't afford all of those fancy-shmantzy time machines, here's a book by Paul Davies that will tell you how to build your own - with some help from Einstein.