COLOGNE'S JEWISH TREASURE: Two rabbis, a stonemason's guild, a Jewish merchant, and the archbishop of Cologne all helped solve the riddle presented by a magnificent medieval prayer book found in Amsterdam.

The article focuses on the rediscovery and return of the 13th-century Amsterdam Festival Prayer Book to Cologne, the city where it was originally created and used in the medieval Jewish community. Topics include the historical excavation and reconstruction of Cologne's Jewish quarter and mikveh, the establishment of the MiQua Museum to preserve Jewish heritage in situ, and the cultural and scholarly significance of the illuminated mahzor as a symbol of medieval Jewish life.