The Bach unaccompanied Sonatas and Partitas for violin (of which their are three each), are a part of every accomplished violinist’s repertoire.  There is nothing comparable in terms of simple elegance and beauty, surprising difficulty, and compositional genius on display from the Baroque period or any other.  To play these pieces well, a musician must have mastery of intonation, tone, a wide variety of bow strokes, and more importantly a deep understanding of each note’s place and purpose in every phrase and how each phrase should be shaped.  Rachel Barton-Pine has been praised for mastering these selections as well as any other, and here she uses a Baroque bow (shorter, and better for representing the style of Bach’s day) and Baroque tuning (about a half-step lower than how we tune today) to convey the feel Bach have had in mind: