This reference work serves as a comprehensive, compact guide designed to provide accurate historical and biographical data regarding the development of opera. Editors Harold D. Rosenthal and John Warrack utilize their expertise in musicology to compile a structured lexicon that covers composers, performers, and the evolution of operatic traditions across various nations. The text aims to provide a reliable, accessible resource for both casual listeners and dedicated scholars of the genre.

Experts and music historians frequently cite this volume as a foundational reference tool for its breadth and clarity. Readers often note the academic density of the prose, which remains accessible enough for enthusiasts while maintaining the rigor required for professional research.