This is a compilation album from The Sixteen, offering tracks dating as far back as 1989. Special credit goes to mastering engineer Tom Lewington for putting together music recorded in quite a variety of sacred and secular acoustic environments; differences remain, but listeners won't be distracted by them. The usual praise of The Sixteen as one of the world's most consistent choral ensembles may certainly be brought to bear here, but there is more. This is among those rare cases where a compilation is preferable to the original source material, for its conception is unique. Director Harry Christophers selects settings of the Agnus Dei from the Catholic Mass (and the equivalent "Behold the Lamb of God" from Handel's Messiah, HWV 56), with movements ranging from the Renaissance to the 20th century. They are not chronologically presented, and they don't need to be; what makes this idea work is that settings of the Mass rely on tradition to a point where they seem, to an extent, to exist outside of time. Edmund Rubbra and Duarte Lobo can bump up against each other without the slightest discomfort. Of course, stylistic changes are reflected in the music, and when entirely new ideas appear, in the Agnus Dei movements of Britten's Missa Brevis in D major, Op. 63, or Poulenc's Mass in G major, FP 89, they have a vaguely revelatory effect. The album has some unusual pieces, like one from early Baroque composer Bartłomiej Pękiel, but Christophers, as usual, provides a final emotional payoff with Samuel Barber's remaking of his Adagio for strings into an Agnus Dei setting. A thoroughly crowd-pleasing compilation that also offers much to consider.