History

The book I used for years is

A History of Western Music - Grout Burkholder, Palisca, by now in its 10th edition.

From the 8th edition onwards, the book has been rewritten from a more contextual perspective. Many connections are made with general history, cultural history with timelines. For teachers there is a lot of background material available: including a complete course that can be imported in a LMS like Moodle, Brightspace and the like.

With a digital subscription of the KB National Library of the Netherlands (www.kb.nl) the Cambridge Histories Online are a great addition.

The same goes for the subject articles of Oxford Music Online (Grove).