The Hubble Space Telescope (HST) has been taking stunning images of space for 20 years. It is one of the largest and most versatile space telescopes and its orbit outside the distortion of Earth's atmosphere allows it to take extremely sharp images with almost no background light. As an observatory in space, Hubble is one of the most successful scientific projects of all time, both in terms of scientific output and its immediate public appeal. It has consistently delivered super-sharp images and clean, uncontaminated spectra over the entire near-infrared and ultraviolet regions of the electromagnetic spectrum. Hubble's observations have opened up new scientific territory and have led to major breakthroughs in astrophysics, such as accurately determining the rate of expansion of the Universe. Hubble - Window on the Universe is a celebration of Hubble's astonishing scientific and technical achievements told via 200 glorious full-colour images. This stunning oversized volume showcases all of the most spectacular - and most recent - images taken by the HST so far. The chapters of the book are arranged thematically (The Solar System in Perspective, A New View of the Stars, Beyond the Milky Way, Exploring Space and Time) revealing the most recent views of a dizzying array of celestial objects such as Pluto and the Kuiper Belt, the birth and death of stars, the beautiful Butterfly Nebulae, Omega Centauri, Stephen's Quintet and the mysteries of dark matter. Feature spreads chart the fascinating history of the Hubble project from its origins and launch in 1990, the discovery and emergency repair of a defective mirror, the impact of four subsequent servicing missions and finally, what the future holds in store for one of the most amazing scientific instruments ever made.