My memory is a little cloudy on this but I think the set dates back to the early 1980s and comprises the Mass “propers” for the various seasons. IIRC (and I may not – it’s been a long time) it was the successor to the “seasonal booklets”) of the 1970s. Since the liturgy has undergone (and continues to undergo) a series of Novus Ordo-inspired neo-latinizations since those days, it might be of interest for historical purposes, but I doubt it will be of much practical use.