The work is 61 pages long and, if played from start to finish would be between 75 to 80 minutes.
But this is more a Well Tempered Clavier of works in harmonics written for solo guitar that I worked on from 1997 through 2021, so it's not intended to be played as a continuous cycle. The studies may be played on acoustic, classical or electric guitar. They are studies as explorations of compositional possibilities rather than didactic works, drawing more from the work of Angelo Gilardino than Sor, Giuliani or Carulli.
The music is scored at concert pitch and most of the studies have two staves, the upper showing how the music should sound and the lower showing how the harmonics are to be played according to their string location and fret location. This is the case for the first twelve studies and the six sonatas. Studies 13-18 are at concert pitch only.
Progressive Studies in Natural Harmonics includes the following:
Gamut and chord index
Practical scales in standard and open D tuning
"Stretch `n Barre Blues" (preliminary exercise)
Study No. 1 in F sharp minor (harmonic change through oblique motion)
Study No. 2 in A major (imitative procedures)
Study No. 3 in E minor (change of mode between dorian and mixolydian)
Study No. 4 in G major (asymmetric and changing meter, lydian mode)
Study No. 5 in B minior (ostinato study, blues)
Study No. 6 in D major (ternary form and modulation)
Study No. 7 in F sharp minor (O Sacred Head Now Wounded)
Study No. 8 in A major (Italian hymn, a. k. a. Come Thou Almighty King)
Study No. 9 in E minor (What Wondrous Love)
Study No. 10 in G major (on Nettleton, a. k. a. Come Thou Fount of Every Blessing)
Study No. 11 in B minor (on Aberysthwyte, a. k. a. Jesus, Lover of My Soul)
Study No. 12 in D major (on Lobben den Herren)
Study No. 13 in G sharp minor
Study No. 14 in B major
Study No. 15 in C sharp minor
Study No. 16 in E major (homage to Dave Brubeck)
Study No. 17 in A minor (on Ebenezer)
Study No. 18 in C major
Sonata in Natural Harmonics in A major (Studies 8 and 3 are used as themes)
Sonata in Natural Harmonics in F sharp minor (two original themes but Theme 1 evokes Study 7)
Sonata in Natural Harmonics in G major (includes Study 10 as first theme)
Sonata in Natural Harmonics in E minor (draws on Study 9 and 11 for themes)
Sonata in Natural Harmonics in D major (uses the two themes from Study 6)
Sonata in Natural Harmonics in B minor ("Morning Trumpet" and an original theme)
The closing sonata adapts the opening of Contrapunctus I from Bach's Art of Fugue as the introduction and coda for the Sonata in B minor.
If you're ambitious you can try to go through the entire cycle but as I've composed and played these pieces I've used this cycle as a grab bag of little interludes to be played in church services (thus the copious use of hymn tunes from the Christian traditions); and taking a build-your-own-sonata approach of playing a selection of the studies as suites or sonatas without going through the whole series. For instance, I like to play Sonata in Natural Harmonics in E minor with Studies 10, 8 and 3 as subsequent movements.