This is a book about yoga. Or at least, it was.

January 2015. High on literary success and familial bliss, Emmanuel Carrère embarks on a rigorous ten-day meditative retreat in rural France in search of clarity and material for his next book, which he thinks will be a subtle, upbeat introduction to yoga.

But his trip is cut short, and he is brought down to earth with a thud when he returns to a Paris in turmoil in the aftermath of the Charlie Hebdo terrorist attack. From then o ...