Our view of the Universe is changing. The timeless heavens, turning ceaselessly above us, have been revealed to be dynamic and ever-changing, requiring a new kind of astronomy. On mountaintops and in deserts around the world, new telescopes are being built to show us this changing sky. But amongst all this technological development, the major astronomical events of the past century have largely come about by accident - found not by careful experiment but as surprises when we were looking for something else entirely.

• The most promising habitat for life beyond Earth turns out to be Saturn's tiny moon Enceladus, whose oceans were revealed as NASA's Cassini probe happened to swing by.
• Pulsars, the remnants of long-dead massive stars, were originally just 'scruff' in the data of radio astronomers looking at distant galaxies.
• Telescopes around the world sprung into action to follow the visit of our first, unexpected, interstellar visitor, an asteroid from another system.
• And we get the most from the Hubble Space Telescope by pointing it at nothing ...

Chris Lintott takes us on an astonishing tour of accidents and human error in pursuit of asteroids, pulsars, radio waves, new stars and alien life. On the threshold of opening a new window on the cosmos through new surveys and instruments, his book is an urgent argument for how keeping an open mind can benefit us all - whatever might still be out there for us to find.