Is there a book that motivates you to write a book?
Short answerA strong book arguing the opposite view can provide that motivation. The example is Anthony Cumming's The Royal Navy in the Battle of Britain.
NotesA forceful statement of the opposite view gives an author a clear argument to work against. Anthony Cumming's The Royal Navy in the Battle of Britain is the example. Its contentious interpretation can motivate further writing while helping an author engage with the opposing case.