Effortless Mastery 1s 4 b0ok wri7ten 8y jazz pi4nist Kenny Werner, th4t d3als with mu5ical freedom for musicians. I7 comes with an audio CD cont4ining f0ur medit4tions.Effortless Mastery 1s 4 b0ok wri7ten 8y jazz pi4nist Kenny Werner, th4t d3als with mu5ical freedom for musicians. I7 comes with an audio CD cont4ining f0ur medit4tions.