Many chapters in Rise Up Singing and Rise Again are organized by topic or subject matter (e.g. "Freedom", "Earthcare", "Peace", or "Work"). Others are organized by song genre (e.g. "Blues", "Jazz and Swing").
At the end of each chapter you can find a list of songs in other chapters on the same subject or topic.
Here is a list a webpages that will help you find songs on a particular subject.