I'm creating a book about how to teach to children. Can I patent the method described in my book?
Essentially, as I understand it, a purely abstract idea such as a "set of mental steps" is not likely patent eligible at this time.
However, patent law is always in a state of chaos, so you should consult with a patent attorney or two before making any public disclosure, just in case there is a way to render the material eligible. (In March of 2013, US Patent law switched from "first to invent" to "first to file", thus any public disclosure prior to filing either a provisional or nonprovisional patent will lose you the right to pursue a patent for any disclosed material.)