The Tanach (mistakenly known as the "Old Testament") is made up of the Torah, Nevi'im, and Ketuvim. The Tanach was canonized in approximately 500 BCE by the Men of the Great Assembly. The Tanach was not originally broken into chapter and verses. The idea of chapter and verses - as well as the breaking apart of Samuel, Kings, and Chronicles - is a leftover from Christians in the 13th century. Before the study of Torah a brocha (blessing) is said in which the person thanks G-d for giving the Jews Torah. There have been many rabbis who have written commentaries on the Torah. Any complete study of the Torah needs to include some commentary from these sages.