"Four Experts" - it was with this headline that the press welcomed Vol. 10 of the encyclopedic Haydn series by the Leipzig String Quartet. Now the ensemble from Saxony doubles our pleasure with all six quartets from Opus 17 on the two CDs of this attractive box expanding our Haydn quartet horizons to include his earlier works. The result is uncommonly rewarding inasmuch as light is shed on a highly interesting developmental advance from divertimento mirth to mature chamber music and straight into the formative years of a revolutionarily new musical genre. For it was first through Joseph Haydn that the string quartet was crowned the king of chamber disciplines. Four instruments performing as equal partners but in different registers mean that the music has to focus on the essentials; no instrumental tricks might help it over possible compositional longueurs. But Haydn's music of course does not at all need such assistance. The ten years of experience that Haydn had gathered in this genre are heard in his Opus 17. The form is clearly more concentrated; instead of creating an entertaining medley of catchy melodies, he limits himself to a few themes from which he develops a movement or an entire quartet. The extraordinary skill of the instrumentalists available to him in Esterhaza inspired him to craft the sparkling passages that repeatedly flash across his scores. The absolutely great moments in this collection also include many a slow movement - for example, the Adagio from No. 3, which takes the listener into harmonically remote fields. In the careful hands of the four top musicians from Leipzig these rarely heard quartets develop a fascinating appeal that could not be more charming.