The collection, dedicated to Philip II of Portugal, is the earliest surviving Portuguese keyboard print.
It contains 24 tientos, 101 liturgical organ versets (kyries and hymn settings), four settings of the Spanish/Mozarabic version of Pange lingua, and four intabulations of Lassus' Susanne ung jour.
Coelho's most important compositions are his tientos, which are very long (200–300 bars on average), multi-sectional pieces.
The harmonic language is simple and clear in sharp contrast to the contemporary Italian composers (i.e., Ascanio Mayone, Giovanni Maria Trabaci and Girolamo Frescobaldi); the contrapuntal techniques are reminiscent of Sweelinck.
Coelho's liturgical pieces are less ornate, and generally employ more strict counterpoint.