After listening to reports from two observers sent to Vietnam, Kennedy responded with a question. ‘Did you two both go to the same country?’ The reader may ask the same of the two editions to be reviewed here. Each consists of two volumes, all of the same trim size and thickness; but one set is red, the other blue, and the differences go on from there. It is necessary to reassure the reader that both concern the same four documents said to contain ‘Aquitanian polyphony’, and in addition one document known as the ‘Codex Calixtinus’ – more precisely the Liber Sancti Iacobi (of Compostela). The contents include a determinate number of musical compositions, in an indeterminate number of variant versions, all dated to the twelfth century, in France.