Cloaked in apparent simplicity, the number 4 conceals mysteries and secrets, especially from a musical standpoint. Intricate internal clocks strike four quarters. Vocal instrumental quartets have long inspired great composers and tortured intrepid musicians. The number 4 emerges in a variety of other musical contexts: Vivaldi’s seasons, the performance of a piece by Bach, metres, heartbeats, neural oscillations, and popular hits that breathe life into listeners and make them cry. Also, 440 vibrations per second have become, over the centuries, the international pitch standard. So, what are the four main ingredients of this book’s recipe? A dollop of music theory, a dash of history, a (generous) spoonful of psychology and as many stories as needed. Serve warm and with a quart of wine.

Daniele Schön is a research director at the Systems Neuroscience Institute in Marseilles, plays the cello, and studies how the brain encodes music and how music affects brain processes.