What is the name of Hebrew book law and comments?

The Hebrew book of law and comments is the Torah (תּוֹרָה), also known as the Pentateuch (in Greek, meaning "five books"). While the Torah itself is primarily law, the comments you refer to are found in the extensive rabbinic literature developed over centuries, most notably the Mishnah, Talmud, and various commentaries on those texts. There isn't one single book containing both the law and all its commentaries.