Just like the traditional music of Christian churches, that of synagogues has been set polyphonically, beginning with the Baroque compositions of Salomone Rossi, using techniques drawing on the Western harmonic tradition. Letter to Kamilla features performances by the vocal quintet Mosaic Voices, which is the resident choir of London's New West End Synagogue. Many of the pieces are arranged by the group's baritone, Benjamin Till, and one of these, the titular Letter from Kamilla, sets a text by Till's grandmother, sent in a letter before she was deported to Auschwitz and murdered. This haunting work is sung in German. The rest are mostly in Hebrew, with two in Yiddish and one in the Ladino language of Spain. Till's arrangements are varied, but in the main, they do not follow on the Mendelssohnian settings of the 19th century German Jewish composer Louis Lewandowski; nor are they modern in style. Instead, they surround traditional melodies with vocables, somewhat in the manner of U.S. harmonizations of African American spirituals (which Till may well know). In addition to exposing non-Jewish listeners to a body of music they may not have known existed, the album is of interest for the synagogue's remarkable acoustic, which renders the close harmonies of the Mosaic Voices in great detail.