Two of the three books come from the late jazz guitarist Ted Greene. Chord Chemistry and Modern Chord Progressions are Greene's companion chord texts. Chord Chemistry reads like an applied theory course for guitar, starting with the basics and moving very quickly through some advanced concepts (polytonal chords, substitutions, voice leading). Modern Chord Progressions is a lexicon of harmonic possibilities, taking common chord progressions (e.g. I/iii/IV/V) and working these through 100s of variations in a range of keys. Both of these books were first published in the 1970s and their look is a little dated (hand-written diagrams) but it is worth overlooking this for the quality of materials.
Voice Leading for Guitar by John Thomas comes from the Berklee Press series (published 2002) and can be likened to a 'modern' take on Modern Chord Progressions. The book begins with a brief look at chord theory (with an emphasis on voice leading) before moving on to a thorough exploration of the II/V/I progression (249 variations in the one key for major alone). After working through major and minor progressions the book applies this chord knowledge with some 'practice tunes' before finishing up with a chapter on advanced chordal concepts.
While there is some overlap of material in the books by Greene and Thomas, I would suggest that all three are useful for players looking to improve their chord playing. Not only should they aid in your understanding of the theory of chord playing, they will also force you to explore new (and hopefully useful) sounds on the guitar that you may never have stumbled across on your own (unless you have a lot of spare time).



