The 32 Piano Sonatas by Ludwig van Beethoven are often referred to as the 'New Testament' of the keyboard literature, following on the 'Old Testament' of J.S. Bach's 48 preludes and fugues in the Well-Tempered Clavier. Brautigam's recordings, part of a series of Beethoven's complete solo keyboard works, have been described as "riveting" and "revolutionary". Contributing factors to the "refreshing directness" that reviewers have experienced in these performances are the widely praised recorded sound and the carefully selected instruments, built by Paul McNulty after originals from 1788-1819 by the foremost Viennese makers of fortepianos. "One has almost the impression of being a contemporary of Beethoven's: one of the first, infinitely startled - not to say shocked - witnesses to this music" (Süddeutsche Zeitung).