Historically, composers have used methods in addition to inspiration in writing music. Regardless of the source materials they used, composers ultimately rely on their musical sensitivity to inform the compositional decision-making. Discuses the rotational aspects of decimals that are created from certain prime-number denominators, and focuses on the prime number 17. Shows how these decimals can be transformed by converting them to different number bases. Looks at the Golden Proportion and its use in creating formal structures. Examines compositional and aesthetic issues arising from using number series to generate the pitches, rhythms, and sections in the Concerto for Organ and Orchestra. This process of composition reveals musical gestures that may not have been discovered using more intuitively based approaches to composition. Shows how musical sensitivity was necessary in shaping the numerically derived material in order to create aesthetically satisfying music.