Continuing the previous two chapters, this chapter describes the use of genre metadata to bridge the semantic gap between audio signal and emotion perception. While lyrics are complementary to music signal and chords describe the harmonic progression and the tonal structure of a song, genre metadata have been utilized to describe the intrinsic form of music. Genre and emotion provide complementary descriptions of music content and often correlate with each other. The two-layer emotion classification scheme introduced in this chapter exploits such correlation and improves the accuracy of emotion classification.