MAA Online Book Reviews: Indexed by author, title, topic and reviewer.
Mathematical Constants: Website of the book by Steven R. Finch. With sample chapters, supplementary materials and further resources.
Non-Newtonian Calculus by Michael Grossman: Includes discussions of general theory and heuristic guides for application.
The Classification of the Polynomial with Real Coefficients: Explains a theory that the algorithm that every polynomial transforms to a source form. On-line summary, CD version.