A melodic process traces a melody's principal motions from its main beginning to its closure. Western tonal music seems built around a handful of different melodic processes. In each of three experiments, we took melodically complete excerpts from fully instrumented recordings of music of the Classical and Romantic periods. The stimuli instantiated either of two different melodic processes. The processes varied across experiments. Subjects judged the dissimilarity of pairs of stimuli. Multidimensional scaling and hierarchical clustering showed that melodic processes and overall properties of contour were important in determining the subjects' perceptions. In a fourth experiment, two-part forms proved perceptually distinguishable from three-part forms. A final experiment which systematically varied both process and form indicated that process and contour can completely mask any perceptual effects of form. On balance, melodic process, contour, and form influence the perception of music in descending order of importance.