As can be seen from my questions, I am struggling to make Mathematica do something useful. The amount of tutorials on the Wolfram web site is a bit overwhelming, especially that I don't have too much time to read them. However, I am commuting for about 90 minutes per day, and having the Mathematica documentation (even just the one that comes with the software) in Kindle-friendly format (I'd even accept pdf) would be a great thing for me. Can I find a downloadable version of Mma docs (in pdf, or even better, in epub/mobi) anywhere?
Mathematica's documentation is also available online in the pdf format, as a tutorial collection. The place to look for it is here. Also, some books on Mathematica are now available as kindle editions, from Amazon. Finally, for those books which have Mathematica notebook versions, you can probably make a pdf from those notebooks for a personal use, if that does not violate the book's license.