The years which are covered in this volume are almost a laboratory experiment in the cultivation of creativity. For nearly a quarter-century, as composer in residence at the Hungarian answer to Versailles, Franz Joseph Haydn was sheltered and sustained by a princely patron who gave him both the opportunity and the contractual obligation to produce a profusion of new music. The result was spectacular: more than 100 symphonies and equally impressive quantities of chamber music, piano sonatas, operas, songs and religious works-virtually all touched with genius.

In its stately, retrograde progress, this massive study is now nearing the end, volumes II to V are in print-some 2500 pages-and when volume I crowns the series it will complete one of the great documentary biographies of our time.

Hard-core Haydn devotees (all other, naturally, would be daunted by the sheer bulk and thoroughtness of Landon's work), reading through volume after volume, must by now be wondering when we will reach the dull parts of a rather quiet, sedentary life. They have not come yet.Naturally there are sections that one passes quickly (bills for violin strings and music paper, for example), but one must be careful. On the page adjoining one such bill is an account of a lawsuit against Frau Magdalena Frumwald, an obstreperous neighbor who had part of Haydn's roof torn down (at 4:30 a.m., April 29, 1769) because she claimed it extended over her property line. Frumwald is only one of many colorful secondary personalities: Haydn's musical establishment at Eszterhaza included an opera company, with all the turmoil that normally accompanies such an enterprise.

Musically, the period covered here is the one in which Haydn nourished the symphony and string quartet from their awkward adolescence into a robust maturity, became a great opera composer (only noe achieving due recognition thanks to the enterprising series of Philips recordings) and made a tumultuous, musically rich passage through his "Sturm and Drang" phase, one of history's most successfully navigated mid-life crises and a clear prefiguration of 19th-century romanticism.

Even those who will be willing to wait for a one-volume condensation weighing less than five pounds might do well to visit their libraries, glance at Landon's monumental work, imeditate briefly on scholarly dedication and be glad it's all there. (Indiana, $45)