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.