Rambam - Book of Love - Laws of Prayer - Chapter 1

This is the second book of the Mishneh Torah of the Rambam, Rabbi Moshe ben Maimon. Laws of Tefillah.
This chapter explains that the counting of prayers and their timing are not stipulated by the Torah, and that women are obligated to participate in prayer. It details how many prayers there are and why they were prescribed, whether one can decrease the number, and if one wishes to add more, what must be added. It also addresses whether the congregation can pray a prayer of generosity or if an individual can add two additional prayers (Musafim).