What Is the Sefer HaHinukh? Originally Published May 3-4, 2019.

Published anonymously in 13th-century Spain, the Sefer HaHinukh - the Book of Education (ספר החינוך) - is a discussion of the 613 mitzvot (sometimes called commandments) of the Torah.  Following up on Maimonides’ lead in his Sefer HaMitzvot, published in the 12th century, this author also listed the mitzvot in the order they appear through the Torah.  (In the 16th century, Gedaliah ibn Yahya credited the authorship to Rabbi Aharon HaLevi of Barcelona (1235-circa 1290), but that has been disputed based on disparity with other of the Rabbi’s works.)  The authorship remains unknown. 

The book speaks to each mitzvah from a literal perspective, from the philosophical roots, from the historical practice, and then gives a summary as to its applicability.  It was written (as stated therein) for the youth of the time to learn on Shabbat afternoons, and gives a reason for each mitzvah.

The format of the book is orderly.  For each mitzvah it presents a definition and the sources in both written and oral tradition; lessons that may be derived from the mitzvah; basic laws pertaining to observance of the mitzvah including penalties for violating it; and who is obligated to perform the mitzvah, and when. 

In the Introduction, the author hints about his identity while stating his purpose (translation from Sefaria):

And now since the 613 commandments are dispersed in the Book, scattered in it, here and there, in different stories that are written in the Book - for a great principle or for the need that is to be found in it - the reader will perhaps not place his heart in the [weekly reading] to see how many commandments he read that week; and he will not arouse his heart to urge himself about them.  Hence I - “the poorest of my thousand,” a student of the students in my time, a Jew from the House of Levi in Barcelona - saw it good to write the commandments by way of the [weekly] orders and in the order that they are written in the Torah, one after the other. [This is] to arouse the heart of the youth - my son and his friends - each and every week about the tally of the commandments after they study that [reading]. And [this is also in order] to accustom them to [the commandments] and to attach their thoughts to the thought of purity; and to the calculation of the essential, before they put in their hearts, calculations of joking and 'what is it to you,' and of 'what is the point.' And [so] 'even when they age, it will not depart from them.'

Seems like a monumental work.  And it has survived - it is for sale on Amazon.