The Hours of the Cross and the Hours of the Holy Spirit are to be found in most Books of Hours. Much shorter than the Hours of the Virgin, the canonical sequencing is the same as with the Hours of the Virgin, Matins through Compline, except that there is no Lauds. These two additional Hours, one after the other, often follow the Hours of the Virgin.
Sometimes, however, there occurs in Books of Hours what are called mixed Hours. In these cases, the individual Hours are integrated within the Hours of the Virgin. Some Horae also mix in the Hours of the Holy Spirit.
Each Hour consists of two pairs of versicles and responses, a “Gloria Patri” followed by an antiphon (A.), a short hymn followed by a versicle and a response, and a prayer, oratio (Or.); there are no Psalms.
The structure and contents of each of the remaining Hours (Prime through Compline) is the same except for the hymn, which is, in each Hour, a different stanza from a devotional poem whose verses form meditations on sequential moments of Christ's Passion.
Each of the separate Hours touches upon a different theme relating to the attributes of the Holy Spirit or the role he played or will play in the history of mankind's redemption. Matins of the Holy Spirit, as seen in the hymn, discusses the Incarnation; Prime, Redemption through Christ's Passion; Terce, Pentecost; Sext, the Apostles' proselytization; None, the qualities of the Holy Spirit; Vespers, the Holy Spirit as Protector; and Compline, the Last Judgment. The Hours conclude with a stanza that invokes the Holy Spirit's aid in achieving eternal salvation in heaven.
Sometimes the Hours of the Cross and the Hours of the Holy Spirit are full Offices. As Offices, they are much longer (equal in length to the Hours of the Virgin) and their structure parallels that of the Hours of the Virgin. These longer Offices appear in manuscript Books of Hours much less frequently than the shorter Hours, and in printed Horae they hardly appear at all.