<p>Rather than buy some book, I would suggest looking around for programs. I know they exist. I applied to 2 research programs as a sophomore (I was rejected from both). How old will you be? The minimum age for research stuff is normally 16. Where do you live? There are normally some local ones that you can apply to. If you want, try applying to math camps. Im not an expert but I know you can apply as a sophomore to most. There is also CTY/EPGY/ other programs where you take academic classes that are good.</p>