The Elegant Universe. Brian Greene
It all began when the file with the book sat on my desktop for several months. Then (surely because everything else had become boring) I finally opened it and started reading. It became impossible to stop. That same evening I tried to buy the book in a store. They said everything that had been delivered to them had already sold out. The next day I ordered it from an online store. But it looks like I will finish reading it from the screen of my pocket computer before the paper copy arrives. It is a little annoying that I did not try installing Pocket DjVu before ordering the book. But now I will have a paper copy to lend to everyone.
An extraordinarily simple and clear explanation of extremely complicated things. And of course it is also very interesting to learn how everything is actually arranged.
You can download it from here: http://koob.mhost.ru/greene/. If the link stops working, I also have the file here.