Constructing Walking Jazz Bass Lines Book V - Building a 12 Key Facility for the Jazz Bassist PT II - Paperbackby Steven Mooney (Author) Building a 12 key Facility for the Jazz Bassist Pt. II Methods for practicing scales, modes & arpeggios. While Building a 12 key Facility Pt. I Book IV in the "Constructing Walking Jazz Bass Lines " series for the upright & electric bassist focuses on practicing jazz standard and bebop chord progressions in 12 keys, a task practised rigorously by the masters of the jazz idiom. Building a 12 key Facility Pt. II Book V in the