Oceanic soundings

Fond of a pun and noting, as many others have, that the word Bach in German means "brook" or "stream", Beethoven is alleged to have said of his fellow composer: "His name ought not to be Bach but Ocean, because of his inexhaustible wealth of combinations and harmonies." The business of charting the enormity and variety of that ocean and exploring its remaining terrae incognitae has occupied scholars for hundreds of years and is the task that now falls to Malcolm Boyd, editor of the Oxford Composer Companion J. S. Bach, and his 40-odd contributors.

Announced as the first in a series on great composers, the book is an encyclopedia with entries on practically anything to do with the life and orks of J. S. Bach. The main section of entries is followed by appendices listing Bach's works, while topics of major significance - St Matthew Passion , "Organ", "Chorale" - have essays devoted to them, which are set in larger type and allowed to run on for several pages if need be.

The Companion is nothing if not exhaustive. There are entries for no less than 17 lesser members of the Bach family, as well as Bach's two wives. The section on Bach himself is surprisingly brief, but refers one to entries for the towns where he spent time - Arnstadt, Weimar, Cothen, Leipzig, etc - where useful biographical summaries are to be found. "Bach's personality" is dealt with summarily in a few paragraphs: this volume, it seems to say, is not the place to go for speculative ruminations about the composer's private life, or even simply what sort of a man he was. The statement "His love of wine, beer and tobacco and the fact that he fathered 20 children is enough to show that he did not scorn life's more sensual pleasures" is about as suggestive as it gets.

Indeed, the Companion conveys a hint of disdain when making fleeting reference to any of the popular lore concerning Bach - his walking hundreds of miles to Lubeck to visit the composer Buxtehude; his Goldberg Variations being written to amuse Count Keyserlingk during his hours of insomnia - but if Bach is treated less as a human being than as an object of scholarship, there are compensations in the form of excellently researched, lucid essays on almost everything you could want to know about the composer.

All the Companion's authors are active scholars and provide a revealing insight into what musicological research into Bach consists of. One thing that occupies many scholarly hours is establishing what happened when, and under the headings "Cantata" and "Chronology" one can read of the painstaking work of Georg von Dadelsen and Alfred Durr in fixing the dates of composition of the early Leipzig cantatas, previously thought to be from quite a different period of Bach's life and leading to different assumptions about the cantata's place in Bach's oeuvre. Another key concept is "Parody" - Bach's reworking of old material to fashion works for new occasions. The Christmas Oratorio and Mass in B minor mass are two good examples of such plundering; the latter was completed in 1749, the year before Bach's death, but is now known to include music written as early as 1714.

The vexed issue of performing and recording Bach is treated diplomatically. Many are the casualties of the revolution in this area in the past 20 years. One such is Karl Munchinger, founder and conductor of the Stuttgart Chamber Orchestra, whose many Bach recordings were admired in the 1960s and 1970s. Münchinger is now a non-person, "bypassed by musical history" in the estimation of the current edition of the Penguin Guide to Compact Discs . Neither is he mentioned in the Companion, although other unfashionable figures such as Karl Richter and Fritz Werner get a look-in.

Areas of research that some might consider dubious are dutifully catalogued. There is admittedly no mention of Queering the Pitch: The New Gay and Lesbian Musicology , which a few years ago took Bach to task for his patriarchal and repressive choral writing. But "Number symbolism" gets a good run for its money. This concerns the uncovering of secret messages in Bach's music by devices such as counting the number of bars in sections of music and performing arithmetic with significant numbers, such as the books of the New Testament . The essay's author comments breathily: "It almost makes one's fingers itch to reach for the nearest score and begin counting!" - one hopes she is being ironic. A point is inadvertently made, that Bach, like an ocean, can with ease accommodate small islands where the natives are a bit strange.

Shorter entries chronicle Bach's fellow composers, his pupils and friends, the instruments he wrote for, genres he wrote in and liturgical and theological concepts such as Lutheranism, Pietism and the structure of the Hauptgottesdienst church service - indispensable for an appreciation of Bach's daily life as Thomaskantor in Leipzig. Entries for the individual cantatas are also invaluable, detailing as much as is known of the date of composition and performance, the text, forces required and the musical structure of each piece. Every entry in the Companion is followed by a bibliography, often referring the reader to periodical articles written in German. It is a serious book, with often quite technical explanations of how figures work, or why Bach adopted a particular fingering for a keyboard piece, but anyone with an interest in the composer will find such things fascinating and worth persevering with.

On the negative side are the Companion's disappointingly poor reproductions, mostly photos of instruments current in Bach's time. Potential buyers may also be concerned at the hefty price tag, but I for one am already wondering how I ever managed without it.

Christopher Wood contributes to BBC Music Magazine .