During the 1950s Penguin faced increasingly stiff competition from rival paperback publishers such as Pan Books, which had started publishing mass-market paperbacks with full-colour pictorial covers back in 1947. Inevitably pressure grew for Penguin to do the same, but resistance to this was strong and the prevailing opinion was that such 'lurid' covers were best avoided. Despite this, the fact remained that these colourful covers were very popular with book buyers and the large sales figures the books generated were in turn attracting authors. The plain typographic covers favoured by Penguin looked old-fashioned by comparison, and it was clear that something needed to be done.

For a time there was talk of Penguin expanding into light fiction or 'Parrot Books' as Allen Lane disparagingly called it, and a new series called Penguin Westerns was discussed at some length. But in the end it was decided to conduct an experiment using full-colour pictorial covers for a series of books that appeared in 1957–58. For this Hans Schmoller brought in the graphic designer, Abram 'Olympic' Games, to act as consultant art director, but the experiment was short-lived and Lane pulled the plug on it when sales figures proved inconclusive.

However, a move away from typographic covers could not be postponed indefinitely. By 1960 Pan was the second largest publisher of paperbacks in the UK, and Penguin, which still held first place, was routinely using pictorial covers. The first sf titles with illustrated covers began to appear in the same year.

To begin with the illustrations were in black and white, though it was not long before colour was introduced, if such a claim may be made for the little flecks of yellow that almost pass unnoticed on the cover of The Midwich Cuckoos.

The illustrations were initially confined within the cover's central white space, but soon they began to spill across the rest of the cover, as shown by The Black Cloud that drifts across the sun and both orange bands with equal indifference.

The release of The Midwich Cuckoos as a film called Village of the Damned prompted Penguin to hastily reprint the novel as a film tie-in. Nominally it was in the vertical cover format with a large black-and-white still from the film pasted across much of the cover, plus some text which misquoted the film's title as The Village of the Damned. This left little room for the title of the novel, the author's name, logo, price and so on, which were crammed haphazardly into the remaining spaces. Not that it mattered as the film was a box office hit and the book no doubt sold well on the back of it.

After the Rain is a post-apocalyptic pastiche of Jerome K Jerome's Three Men in a Boat woven through with the Orwellian satire of Animal Farm. The cover is notable for its bolder use of colour but also for its early example of the scribbled line drawings that would make Quentin Blake a household name years later, when he went on to illustrate Roald Dahl's classic childrens' stories such as Charlie and the Chocolate Factory and James and the Giant Peach.

The appearance of Aldiss's anthology marked a turning point for Penguin sf that would lead to the launch of a separate science fiction series seventeen months later. Where the idea for the cover design came from is uncertain, although the usual approach with anthologies was to select one story and link the artwork to that. Seen this way, the similarity of the contraption on the cover to the mechanical bride in the upper pane of The Large Glass by the iconoclastic French artist, Marcel Duchamp, points to the best story in the collection, Walter M Miller's Command Performance, in which a young woman's battle against telepathic and bodily penetration parallels the psychosexual symbolism of Duchamp's masterpiece.

This interpretation of the cover as a science-fictional rendering of The Large Glass is made more interesting by the fact that it prefigures the use of abstract and surrealist paintings on the covers of the sf series that followed it in 1963.

The blurb on the back of The Outward Urge describes Lucas Parkes as Wyndham's "technical adviser", although a clue to his true identity may be found in Wyndham's full name, which was John Wyndham Parkes Lucas Beynon Harris. But like The Seeds of Time three years earlier, the blurb again sold Wyndham short, this time announcing "four exciting episodes" instead of five. The error was corrected when the book was reprinted in 1964.

The Day of the Triffids and The Seeds of Time were also reprinted with illustrated covers, but first prize went to The War of the Worlds for a filigreed drawing of a Martian tripod striding purposefully across the cover like a panzer tank on stilts.