The Albatross Modern Continental Library
I received this in the mail from bookmooch today. I was really intrigued by the old Penguin-like cover so I looked up the publisher, Albatross, online. Apparently, the entire style of the class Penguin books was based on the Albatross look! Albatross was a 1930s German publisher of English-language books that was extremely successful until the Nazis shut them down in 1939. Luckily the heads of the company escaped and went on to work for other publishers (one of them in fact wound up in charge of Penguin's American division).
This link has an interesting page about Albatross: http://www.tauchnitzeditions.com/albatr