You know this, but for others: the Book of Hours consisted of scripture readings, including Psalms and Canticles, to be read at various hours through the day and night.
A Canticle is a song or prayerful monolog from the bible. Major canticles include the praises from the Blessed Virgin Mary (”My soul magnifies the Lord, and my Spirit rejoices in God my Savior...”), from Zecharias (”Blessed be the Lord, the God of Israel; he has come to his people and set them free...), of Simeon (”Lord, now let your servant depart in peace...). There are many Old Testament Canticles, too, such as those of Moses (”...horse and rider, He has thrown into the Sea”).
Nearly the entire Book of the Hours is from scripture, and nearly the entire gospel is contained within, but there are significant portions that Protestants do not recognize as scripture, such as Canticles of Tobit, Judith, and an extended version of the Canticle of the Three Youths Saved from the Furnace from the Book of Daniel.
Thank you for your insight.
The books you refer to are not part of Holy Scripture, they were not recognized in Nicea for good reason and it had nothing to do with Protestants, as Martin Luther wasn’t around.