Officium Parvum Beatae Mariae Virginis: Officiumque Defunctorum Juxta Brev. Cist. [Trappist Little Office of the Blessed Virgin Mary]
by Order of Cistercians of the Strict Observance

In Latin. 1930 Ex typographia Ord. Cist. Strict. Obs. (Westmalle, Belgium), 3 1/2 x 5 1/4 inches tall black pebbled cloth hardcover, gilt lettering to spine, all page edges red, green pattern endpapers, printed in red and black ink, illustrated with black-and-white engravings, [6], 235 pp. Slight soiling and moderate rubbing and edgewear to covers. The front joint appears to have been glued at some point to reinforce the binding, which is quite solid. Some chipping at spine caps. On the half title page, ink prior owner name, accession number and monastic library stamp from the Trappist Abbey of Our Lady of Gethsemani, near Bardstown, Kentucky, famous for being the home of monk, social activist and author Thomas Merton from 1941 until his death in 1968. Another Abbey of Gethsemani stamp on a rear free-endpaper has Gethsemani lined out and Genesee written in, suggesting the book was later used by the monks at Abbey of the Genesee, a Trappist monastery in western New York founded by Gethsemani Abbey in 1951. A number of pages have mild to moderate staining or soiling, especially at the fore edge margins. Despite all these detractions, still a solid, complete copy of this scarce Trappist edition of an important liturgical prayer. Scarce. OCLC (No. 19363495) locates less than ten institutions worldwide. 

The Little Office of the Blessed Virgin Mary, in a 1930 edition prepared by the Order of Cistercians of the Strict Observance, better known as The Trappists, a Catholic religious order of cloistered monastics that branched off from the Cistercians.

The evidence suggests this volume was used by the Trappists during Thomas Merton's tenure at Gethsemani Abbey in Kentucky, and was given to the monastery founded by Gethsemani, Abbey of the Genesee in New York, sometime after its founding in 1951. So there's a good chance Thomas Merton (Fr. Louis to his monastic brethren) used this to observe the Little Office of the Blessed Virgin Mary at some point.