Many musicians (whether composers, performers, or writers) see rhythm as the most fundamental and indispensable element of music. But paradoxically, this general recognition of the paramount importance of the durational parameters of music (rhythm and metre), that ended up working against them: the 'naturalness' of rhythm and metre, made theorists feel too confident that their own aesthetic preferences reflected the essence of these parameters. The result is the subordinate position attributed to rhythm and metre by the traditional music theory, which seeks to understand them in relation to pitch structure. This thesis instead proposes a purely durational approach which assesses the operation and qualities (mainly salience and kinesis) of rhythm and metre, and their interaction with other music parameters. The proposed model is supported by a series of experiments and illustrated in three analytical case studies.