In the 18th century, works for unaccompanied solo instruments were more often improvised than written down. J.S. Bach bucked the trend and not only composed his cello solos with infinite care and personal insight, but also aimed high and produced six substantial suites. Composed in his “middle period” at the court of Cöthen (1717-23), they all follow a similar pattern, but probably weren’t conceived as a set. Steven Isserlis is a master at varying the character of the four core dances—allemande, courante, sarabande, and gigue—which recur in every suite. Although they were conceived as secular works, Isserlis views them symbolically as embodying three kinds of “Sacred Mystery”: Joyful (1 & 4); Sorrowful (2 & 5); and Glorious (3 & 6). Throughout, he plays with a warm, generous tone on a Stradivarius of 1730.