Why is the sky blue? It’s a question that has been asked for at least 2,500 years and presumably much longer. In this book, Hoeppe documents our attempts to answer the question, starting in the fourth century BC and continuing up to the present. The roll call of thinkers that have contributed to the answer is iconic, including Aristotle; the Arab philosopher, Al-Kindi; Leonardo da Vinci; Isaac Newton; John Tyndall; James Clerk Maxwell; John Strutt (later Lord Rayleigh) and Albert Einstein.

This is not an effortless book to read. It has been translated from the German original, published in 1999, but the translation is graceful and unforced. However, various explanations for the sky’s blue colour that have been proposed throughout history require a little work to understand, particularly as they become more sophisticated over time. Nonetheless, they are still accessible to any reader who is willing to make the effort.

It seems every science book these days must have a perfunctory chapter on global warming, yet the final chapter on this topic in Why the Sky is Blue is out of place. Hoeppe provides a brief summary of what we know about anthropogenic climate change, tenuously linking it with his topic. “The fact that the warming trend will not have an immediate effect on the colour of the sky can be of little comfort,” he explains. This chapter is largely irrelevant and should have been left out.

The subject of this book is interesting enough in its own right, but equally importantly, it is an informative case study of the ways that human thinking has progressed in our attempts to understand the world in which we live. Like so much of modern Western thinking, we start with the ancient Greeks and move through the Arab philosophers to the European Renaissance before reaching the scientific revolution and our contemporary explanations.

It’s easy to scoff at now discredited theories from the past. They can sometimes seem simplistic or just plain weird. However, the cases presented here demonstrate that, within the constraints of their time, they are often ingenious and the product of much thought and consideration. At the risk of falling into the intellectual mire of post-modern relativism, this also raises the question of how weird our current scientific theories might seem in the future.