What measures 11 inches square and 7 inches high, weighs 21 1/2 pounds and takes 10 days and nights to play?

Answer: A new box set jam-packed with 200 CDs that contains every note composed by Wolfgang Amadeus Mozart in his short 35 years of life.

Just in time for the 225th anniversary of the composer's death on Dec. 5, Decca and Deutsche Grammophon have combined forces to issue this compilation, mind-boggling in its thoroughness and admirable in its scholarly depth. There are other “Complete Mozart” sets on the market, but this one has fair claim to boast that it’s “completer” than the rest.

Talk about your embarrassment of riches! Chronologically, the compilation starts with Mozart's first known compositions, two fragmentary Andantes in C major for harpsichord lasting 17 seconds and 14 seconds respectively, written in 1761 when he was 5 years old. It ends with his Requiem, left unfinished at his death in 1791.

In between are not just all 27 piano concertos, 41 symphonies, every opera, song and sonata, but many alternate versions, fragments, arrangements of music by Handel and Bach and even works whose authorship is in dispute.

Of particular historical interest is the world premiere recording of a recently discovered “lost song” that Mozart apparently composed in collaboration with Antonio Salieri. Written in 1785, Mozart’s contribution to “Per la ricuperata salute di Ofelia” (“For the recovered health of Ophelia”) consists of just two stanzas lasting under a minute and a half. But the elegantly simple tune is instantly recognizable as the work of the composer.

Among the extras packed into the sturdy box are five collector's prints of Mozart autograph scores, the last-known portrait and a letter to his father. There are also two hardcover books -- a new biography of the composer and a work-by-work commentary -- plus a booklet presenting the numbering of the Salzburg Mozarteum Foundation’s forthcoming new edition of the Kochel catalog of Mozart‘s works.

There is so much material here it would take weeks or months to survey thoroughly. And the suggested retail price tag of $479.98 means a significant financial commitment. Definitely not for the casual listener, but for serious Mozart lovers it’s a treasure trove. (AP)