The Darkroom Cookbook by Steve Anchell and Troop is a good book that discusses chemistry, formulations, and considerations.
Insofar as formulations that are commonly used...you can find the recipes for Smith's amidol and ABC Pyro on the Azo Forum
www.michaelandpaula.com
Another site that has formulations for developers posted is
www.unblinkingeye.com
Beyond that you can find a lot of different photo formulations online by doing a google search for
photo chemistry formulas.
If you want an understanding of film density and paper reflection density then the Ansel Adams series (
The Negative and
The Print are good entry level texts.
Another excellent text is
Beyond The Zone System by Phil Davis. A dry and highly technical work but very good.
That probably will keep you busy for a little while. Good luck.