Sam Kean
2017 | 384pp | £20
ISBN 9780857525123

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Sam Kean – Caesar's Last Breath

Julius Caesar was infamously murdered in 44BC on the floor of the Senate by his colleagues, and with his last breath, dispersed 25 sextillion (2.5 × 1022) molecules into the atmosphere. In any given breath you take, the odds are you’re breathing some of them in.

Sam Kean’s book Caesar’s last breath discusses the make-up of the air around us, and how its components have quite literally shaped our planet. In the opening chapters, Kean explains with style and humour how our atmosphere came to be, before moving on to how humans have interacted with the air, and finally, how we are affecting the atmosphere.

For me, it was the human interest stories that made this book an excellent read. I started it half-expecting to find the subject a little dry, but the way the author layered the details of the atmospheric chemistry with people’s stories drew me in. The tale of Harry Truman, the belligerent man who refused to leave his home on the slopes of Mount St Helens despite being warned of its imminent eruption, is a particular highlight. Kean tells of how Truman himself must have vaporised as he was engulfed in hot volcanic ash, his body becoming part of the air that you or me might very well be breathing now. I found myself really caring about the people being discussed, and hoping for happy endings in each chapter. All the while I was learning – about the production of fertiliser, for example – without quite realising it.

In short, this book does exactly what a good popular science book should do: teaching the subject without being preachy or condescending. It’s light and witty in tone, great at keeping you engaged in the subject, whether chemistry or history. I look forward to seeing what Kean publishes next – whatever the subject – as he has proven in this book that he can make gas entertaining for 300 pages.