Books I recommend

Here, three very nice books I found recently:

1. Steven H. Weintraub , Differential forms , A Complement to Vector Calculus, AP, 1997. This is a quite self-contained introductory  book to differential forms. No previous formal requisites are assumed and the necessary background from basic differential geometry is introduced. [Amazon link]
   
2. Frank Wilczek, The Lightness of Being, Mass, Ether, and the Unification of Forces, Basic Books, 2008.  This is a bedtime book for physicists, written by on the most brilliant physicists of our time.  I quote: "Matter is not what it appears to be. Its most obvious property—variously called resistance to motion, inertia, or mass—can be understood more deeply in completely different terms.The mass of ordinary matter is the   embodied energy of more basic building blocks, themselves lacking mass. Nor is space what it appears to be. What appears to our eyes as empty space is revealed to our minds as a complex medium full of spontaneous activity." "The universe is not what it used to be, nor what it appears to be." [Official site].
3. Guy MacLean Rogers, Alexander: The Ambiguity of Greatness, Random House Trade Paperbacks [Amazon link]. If you want a vivid and historically accurate description of Alexandre's conquest of Asia and Persia, this is a very good book. I was actually motivated by the similar course offered in edX.