In 2010, the BBC interviewed a Wiltshire man named Steve Hare who'd been collecting Penguin paperbacks so assiduously that he'd amassed over 15,000 titles. In fact, they no longer fit inside his home, and had "overflowed into a garden outhouse." Mr. Hare is not alone in his peculiar obsession. The Penguin Collectors Society boasts over 500 members (which may seem a small group, but remember, this is a club whose sole purpose is to collect one very particular kind of typically low-value book), and a quick search on Pinterest or Flickr will turn up dozens and dozens of bookshelves packed to the brim with those brightly colored spines.

When, on this day in 1935, the very first Penguin paperbacks were released, there were only ten titles, including some authors who are still widely read (Agatha Christie) and others to whom time has not been so kind (Susan Erzt). In the years since as the fabulous book Penguin by Design chronicles, the trim little books evolved from throwaway commodities into aesthetic statements, plastered on everything from commemorative mugs to postcards to two different types of wallpaper.

While the iconic orange stripes and simple sans serif typeface are perhaps the most indelible feature of the Penguin paperback, the examples below prove that with its evolution, Penguin has continued to push the boundaries of what makes a book cover smart, coveted, and collectible.

Hemingway's classic novel was included in the original ten Penguins and features the name of Penguin's original parent company, The Bodley Head. The paperbacks' clean, crisp style sold so well (reportedly more than 3 million copies in the first year), that a year later Penguin struck out as a solo company.