I obtained this set specifically for Pinnock's scintillating traversal of the Goldberg Variations (S.988), also available in out of print
Bach: Goldberg Variationen
Bach: Goldberg-Variationen; Italienisches Konzert [Germany].
Turns out this entire set is an absolutely superb reading of three quarters of Bach's published Clavier-Übung (the fourth quarter is for organ).
These recordings were made in the early-'80s, in different locales on different instruments, yet the sound is consistently excellent, spatial, and crystal-clear. The instruments are mostly newly-built two-manual harpsichords based on classic instruments. The exception is the Belgian instrument of 1646 used for the Goldbergs.
Pinnock's technique and artistry are really outstanding, and his work is a worthy tribute to "Old Bach," holding its own with Glenn Gould.