As someone who helped in the editing of this project, I am altogether loath to praise it in a commercial forum. But I really must wonder what the above foolish critique from *Publishers Weekly* is about. Talk about unprofessional skimming. Is it better to include a truly minor composer (Reynaldo Hahn) than a leading young American violinist (Hilary Hahn)? What of the reviewer's clear implication that there are no pictures of Mozart (there are several) or Salieri (there is a silhouette), or that it would be better to omit any photos from the nitwit movie (*Amadeus*) through which most laypeople recently have become misguidedly familiar with these two figures in music history?
Even if it's called an encyclopedia, it is altogether informed by one person's judgment and taste -- as if it could ever have been otherwise.
As for the "numerous" errors alleged, of which only a trivial charge concerning an omission holds up, one disputes the book's report about Mahler's departure from the Vienna Court (today State) Opera, countering that he was not fired but resigned. Alas for the skimming *PW* reviewer, Grove's explains it baldly: "... he was again forced to look elsewhere."
So you can safely ignore this particular *PW* review. Buy Libbey's work to read and decide for yourself how solid it is, how useful for you in your listening, and where you may wish to quibble, if you do.