I don't really go in for Penguin's Peregrine series. The books are too high-brow for the likes of comprehensive school educated me and I've never really felt that the cover designs hang together or stand out that well, unlike their aviary-mates. But Graham Bishop's cover for Y4 (Shakespeare's History Plays), first published by Peregrine in 1962, caught my eye and makes me think further investigations might change my mind. '62 was the year Peregrine's were first published, The Penguin Collectors' Society's Penguin Companion describes them as, "uncompromisingly academic", AKA "a bit dull". To start off with they were all about literary and historical criticism then in the '70s, the focus turned to more sociological matters, AKA "still a bit dull".
OK, "dull" is probably quite unfair but what definitely isn't dull is that lovely mark by the masterful Hans Schleger. If you're quick you could pick up a used copy of Pat Schleger's book on Hans for a ridiculous 98p on Amazon.