The best short education I can give you is as follows.
Hardenable alloys and tool steels are the only type of steels that can be correctly/throughly heat treated. I would be typing for an hour to explain all there is to know you for just the basics. (and I am not a metallurgist) There are a dozen or so tool steels each with its own specific use and application.
I highly suggest that you go to a library or search the web to educate yourself in the science and art of metal alloys/tool steels and heat treatment of it.