Fenaroli’s Book IV contains unfigured basses. Without figures, how does a performer know which chords to use? All the patterns introduced in the previous three books are employed in Book IV, so instead of asking “What chord comes next?” ask “Which pattern is this?” Thorough knowledge of the patterns will allow one’s memory to take over and aid the completion of a realization. In a beginning level of realization, the right hand will play mostly consonant chords. At an intermediate level, the right hand will add carefully prepared dissonances and small melodic figures. At an advanced level, the realization will feature extended melodic imitation and counterpoint.