This is Alain's mature version of Bach. She had previously recorded the complete Bach works twice. This version was, according to herself, determined by the availability of historical organs contemporary with Bach. Those organs are not as easily played as the moderns 'baroque' instruments and must be played more slowly. Also, many of the historical organs are not as well kept as would be desirable.
Even so, Marie Claire Alain shows complete mastery of this music. She manages to blend melody and harmony perfectly and both counterpoint and expressive emotion are perfectly rendered. This is true about preludes and fugues but also of chorales and triosonatas: everything is natural, music flows, subtly expressed.
As has been said in the press, Alain manages not to impose her personality upon the music: she just plays and expresses what the music is meant to express. All phrases are natural, all tempo shifts are suggested by the score. A perfect achievement.
The organs are also very interesting. You will find instruments by G. Silbermann, A. and F.C. Schnitger, Chr. Müller, an impressive Treutmann (formidable 32' posaunenbass) and also, for the concerts, a modern Kern.
For anyone seriously interested in Bach's organ music this is a must have.