The 5 Minutes Reading series from Musical Contexts provides key musical knowledge on a range of popular KS3 Music topics, units and genres in an easily laid-out format which can be used flexibly in a range of different contexts such as:
'silent' lesson starters/intro quizzes/DOITNOWs
cover activities
homework tasks
revision of musical knowledge
developing literacy and reading in music lessons
 
Each A4 5 Minute Reading is available in PDF and editable and customisable Word document formats and comes with supporting images, illustrations and graphics to support the knowledge in the text.  There's also a musical quote related to the focus of the reading by composers and musicians and "Questions to think about" prompts which can be used as a stimulus for class discussion, or answered in prose.