Essential Science Fiction #4 'When Worlds Collide' and the sequel 'After Worlds Collide' by Philip Wylie and Edwin Balmer. When Worlds Collide is a 1933 science fiction novel co-written by Philip Wylie and Edwin Balmer; they both also co-authored the sequel After Worlds Collide (1934). It was first published as a six-part monthly serial (September 1932-February 1933) in Blue Book magazine, illustrated by Joseph Franké.

Sven Bronson, a South African astronomer, discovers that a pair of rogue planets, Bronson Alpha and Bronson Beta, will soon enter the solar system. In eight months, they will pass close enough to cause catastrophic damage. Sixteen months later, after swinging around the Sun, Bronson Alpha will return to pulverize the Earth and leave. It is hoped that Bronson Beta will remain and assume a stable orbit.

Five months before the end, desperate mobs attack the camp, killing over half of Hendron's people before they are defeated. With the rocket tube breakthrough, the survivors are able to build a second, larger ship that can carry everyone left alive (originally there was room for only 100 of the roughly thousand people Hendron had recruited). The two American ships take off, but lose contact with each other. Other ships are seen launching from Europe; the French ship's tubes melt, causing it to crash. The original American ship makes a successful landing, but it is unknown if anyone else made it. The survivors find that Beta is habitable.

The sequel, After Worlds Collide, details the fate of the survivors on Bronson Beta.