Aside from the core liturgy of the Hours themselves, a Book of Hours was often expected to contain other prayers, the exact ones varying from book to book. This made each individual copy more useful, and made it so that an owner who only had one manuscript was still able to live a fulfilling personal religious life.

After the calendar in many Books of Hours were readings from the Four Gospels of the New Testament. These readings were standardized, and contained passages on the nature, birth, and resurrection of Jesus. This allowed for Bible study for those not wealthy enough to own a full Bible. The illustration style for the Gospel readings varied– sometimes all four got a page illustration, sometimes only the Gospel of John, and sometimes they all got a fancy initial or less.

Mark the Evangelist is shown writing his Gospel, accompanied by the winged lion which is his standard symbol. This book's artists decided to give Mark a large image rather than just an initial, allowing them to show their skill at architectural and animal designs.

Many Books of Hours also contain prayers designed for certain periods unrelated to the daily cycle of the Hours themselves. The seven Penitential Psalms, poems to be read when atoning for sin, were often included, usually immediately after the end of Compline. They were almost always followed by a Litany of Saints, a list of holy people who would be asked to pray on the reader’s behalf. Illustrations for this section vary, although tend to fall into one of two patterns: either Jesus ruling over the end of the world, or King David, author of the psalms. Depictions of David were often able to demonstrate the process of atonement, showing him repenting for his sins before God.

King David is shown praying at the beginning of the Penitential Psalms section. The user was thus able to see David's own repentance as they read his words about it, allowing them to put themselves in his shoes and tie their penitent prayers to a Biblical source.

Some prayers were more personal, and whether they were even included depended on the patron. The most common of this is "Obsecro Te", in which the reader begs the Virgin Mary to pray on their behalf. This passage had no specifically defined place in the Book of Hours, and only some include it at all. It was a chance for the ritual features of the Book of Hours to overlap with the personal interests of individuals who may have had more or less of a connection with this text and with Mary, and where it ended up can show a modern reader its priority. In some cases, it's the first thing in the book, positioned for focus; in others, it's at the end with other auxiliary prayers, to be read as needed.

A historiated initial marks Obsecro Te with an image of the Madonna and Child. Mary is shown as motherly, emphasizing how the speaker of this prayer wants Mary to care for them and treat them with kindness.