Bloch was rather careful when he used a form based title. His sonatas, string quartets, and symphonies do follow basically correct procedure, no matter how rhapsodic or personal the expressive nature of the piece might be.
This is significant since the cover of the printed music of this piece does not mention the words violin sonata, although the first page does, in parentheses, in much smaller print. This is a one movement, 20-minute work.
Bloch breaks other conventions and assumptions in the writing of this piece. Although he was a master of compositional techniques, or maybe because he was a master, Bloch could break some of the most basic rules of Western harmony. Most prominently he uses parallel fifths in abundance. At the time of these pieces writing these intervals and the use of pentatonic scales represented the exotic and the orient.
Furthermore, Bloch is almost always identified as a Jewish composer. Yet midway through the piece he turns reflective, and the violin intones a Gregorian chant melody, Credo in Unum Deum.
Although this might be out of line with the accepted portrait of the composer, the fact is that he was never religiously dogmatic, rather he felt a part of the history and passion of his people's history. So we can see this as a more universal expression of worship.
Much of the other thematic material is not that complex. For example the opening motive is nothing more than an arpeggiated major fifth. But from such simple ideas Bloch weaves a serious, yet peaceful work. This is in great contrast with his Violin Sonata No. 1, which is turbulent and tortured in expression.
The "Poeme Mystique" was written quickly in November and December of 1924, in Santa Fe, NM. It was premiered On January 24, 1925, in a private concert in New York City by the dedicatees, violinist Andre de Ribaupierre and pianist Beryl Rubinstein.