Before Alex Steinweiss created the first “original” poster-like record album cover art, minimal art and type were printed on the inner record “sleeves”. The sleeve is technically not a record album cover (although it does cover an record), which before the 33-1/3rd rpm long playing (LP) record was invented held a single 10 or 12 inch recording disc. It was usually an individual craft paper (sometimes cardboard) wrapper that protected the fragile shellac disc inside from scratching and dust. It also normally had a round hole in the middle to reveal the record label.
It was understood that recording discs were too easily damaged without some kind of protective covering — even more so later in the vinyl era. This rare collection of record sleeves includes, American, English, French and Spanish versions of the same device produced with varying levels of aesthetic quality. My favorite is the Decca sleeve (below) for its Futuristic-abstract-dynamic design in one color.
(Thanks to David Cohn)