What is Reharmonisation? (An introduction to Mark Levine)

One of the biggest parts of jazz reharmonisation is chord substitution.  Most reharmonisation comes from substitution one chord for another, or several others.  It is important to look at chord substitution is we want to get a full definition of what jazz reharmonisation is.
So far we've seen modern examples of reharmonisation in action - before undertaking this project it is important to look at reharmonisations roots, by studying its definition from a renowned, traditional jazz pianist.

Mark Levine is a well known and respected jazz pianist, who's playing has inspired and taught many musicians worldwide.  He is also a respected author, having written several critically acclaimed jazz textbooks.

Below is an excerpt from his textbook "The Jazz Piano Book", where Levine talks of chord substitution within reharmonisation:

"Jazz musicians like to substitute chords" says Levine.  Levine's book is full of complex jazz harmony diagrams, which show chords being reharmonised in different ways.  Some of the following posts will show some of these diagrams, showing how complex or simple jazz reharmonisation can be.