This is the second book of the Mishneh Torah of the Rambam, Rabbi Moshe ben Maimon. Laws of Reading the Shema.
This chapter explains that the Shema is recited twice daily, how many sections it contains, the reason for reciting the section on Tzitzit, the laws of the reading, whether and what to recite, the proper liturgy, who established them, whether anything can be added or subtracted, who failed to say "Truth and Sustain" in the morning, whether the second blessing was placed before the first, and whether one began with one blessing and ended with another. It also covers the timing of the reading in the morning and evening.