There are pieces that every violinist wants to master and play passionately, I know do. Which ones are at the top of my list? Bach's incredible Unaccompanied Violin Sonatas and Partitas. Here is Nathan Milstein giving a masterful performance.
Bach's Sonatas and Partitas (BWV 1001–1006) are a set of six works rich with emotional variety and depth, complex harmonies, advanced technique and timeless melodies. Bach known as a prodigious organist and harpsichordist was also a violinist from a young age, which if these pieces are any indication, must have been quite the violinist. Some would say that this collection is the peak of polyphonic writing for a non-keyboard instrument and has taken violin technique to new heights as well. Though there were other solo pieces for the violin, Bach's collection was at a whole new level of technique. Those that were first to work on them were said to believe the pieces almost impossible to perform.
Bach started composing this collection in 1703 and finished them around 1720 when he was Kapellmeister in Köthen. Aside from his geographical area, the Western world was only really exposed to them in 1802 when Nikolaus Simrock published them in Bonn. The sonatas follow a four-movement pattern: slow-fast-slow-fast, which was not unusual for the Baroque period. The Partitas on the other hand are unorthodox dance-form movements in their structure, which works well with their improvisatory feel.
For violin students that are interested to start on the Sonatas, make sure that you are in Suzuki Book 6 or something comparable. Most of the pieces will still be very difficult, but some of them will be available to you to work on. Remember that these pieces are not meant to be worked on just once, but throughout your life. Don't give up and the rewards will be great!