Language of the Spirit: An Introduction to Classical Music. By Jan Swafford.Basic; 321 pages; $28. 

JAN SWAFFORD’S new book, “Language of the Spirit”, is a self-guided tour. “When a piece [of music] or a composer grabs you, go out and look for more on your own,” he says. And he has plenty of suggestions to get you started on streaming services such as Spotify or YouTube.

The “classical” genre on Spotify comes some way down the list, and classical buffs have been fretting for ages that audiences are getting greyer and smaller. Even so, many people have at least a passing acquaintance with some of the superstars of the classical repertoire: Beethoven’s Ninth Symphony, say, or Mozart’s “Eine kleine Nachtmusik”, or Handel’s “Messiah”. If that has made them wonder how to put these works into context, this introduction to classical music is just what they need.

Mr Swafford is a music writer (who, among other things, has written a scholarly but highly readable biography of Beethoven) as well as a composer, and has been teaching music for decades, most recently at the Boston Conservatory. This book distils his experience of passing on his knowledge and experience to others, and making it enjoyable for them.

Music has been part of human life almost from the outset: archaeological digs have turned up flutes at least 40,000 years old. But the sort of Western classical music this book covers did not really get going until monks in the 11th century AD found a way of writing it down, which made it possible to conceive and precisely re-enact long and complex pieces.

The book starts at the beginning, with a section on music through the Middle Ages and the Renaissance, and then proceeds through the various periods—Baroque, Classical, Romantic, Modernist and beyond. Each period is introduced with a brief essay on the new and exciting things it brought, followed by individual essays on the great composers of that time. The plan is not particularly original, but the execution is. Thumbnail sketches of the composers bring them to life as individuals and as musicians, and explain how they relate to the artistic and political environment of their time.

Reading about the classical giants one after the other, you begin to feel that their fame came at a high price. Many of them were child prodigies (Mozart being one of the best-known examples), who were mercilessly pushed to perform; most were plagued by money troubles and ill health throughout their lives; and few enjoyed satisfactory personal relationships.

Musicologists generally agree about the brightest stars of the classical repertoire, and here they all are, above all Bach, Beethoven, Handel, Mozart and a raft of Romantics, from Schubert to Wagner. Mr Swafford also thinks a lot of Haydn and, being American himself, gives prominence to a number of American composers. When it comes to the 20th and 21st centuries, the names proliferate and judgment becomes more difficult, partly because “history has only begun to do its job of deciding who thrives and who fades”; and partly, he says, because media, and particularly online media, have given music a new kind of immortality.

Between the stories of the composers, Mr Swafford slips in many interesting digressions. One is an excellent explanation of the difference between tonal music, based on scales and keys, and the atonal sort, which dispenses with such conventions. Another is an evaluation of the early-music movement (using historical instruments and performance) that “really came of age in the 1970s.”

A third is about the complicated art and science of piano tuning. The interval between each note is determined by a mathematical ratio, and the 12 notes in an octave get you to a higher or lower version of the note you started on. But if you observe exactly the right distance between each note, you end up, for reasons that are still not clear, with an octave that sounds slightly out of tune, so the discrepancy has to be redistributed among all 12 notes. This “tempering” can be done in a variety of ways.

All the while, Mr Swafford entertains as he informs. But in the end, music to him is a thing unto itself, “a language of the spirit—its essence can’t be captured in words.”