As part of the celebration of its 50th anniversary, this book paints a portrait of the European Southern Observatory in accessible text and stunning images. Although it presents some historic detail, it is not meant to be a formal history of ESO. Rather, we have focus sed on ESO’s achievements — on the magnificent telescopes and instruments that enthral anyone visiting them, and on the scientific breakthroughs that they regularly produce. Our visual journey tries to give a feel for ESO as a scientific organisation and to present a cross-section of the many parts that combine in making it the successful endeavour that it is.

In a book like this, it is impossible to cover the topic completely, and also to describe the many wonderful scientific and engineering breakthroughs made outside the ESOsphere. It is equally not possible to give proper credit to the many people who deserve it. The limited space has only allowed us to introduce the Directors General who have been at the helm of ESO. Anyone interested in a much more comprehensive history of ESO should read Jewel on the Mountaintop by Claus Madsen (see p. 254), published together with this book, as the other half of what can really be seen as a complementary set. We have however made space to show some of the many unsung heroes who usually remain invisible, but who represent the cement that holds the organisation together.

The last part of the book provides credits for the many images, further literature about ESO and also the first ever full overview of ESO’s telescopes.