Arguably the most prominent poet of late 16th-century Italy, Torquato Tasso (1544-1595) produced throughout his career more than 1,500 lyric poems, collectively known as Rime. About 180 of these poems, for the most part madrigali liberi, enjoyed a remarkable musical fortune in the late 16th and early 17th centuries. Indeed, between 1571 and 1620 they received about 500 polyphonic settings by composers of varied geographical provenance, ranging from central Europe to Sicily. In this dissertation I explore this vast poetic-musical repertoire, to which both literary scholars and musicologists have so far devoted limited attention. In so doing, I pursue two main research avenues: the first is to understand how these poems became musical hits; the second is to determine how composers set them to music, providing a snapshot of compositional personalities and schools. The dissertation is divided in two parts. Part I is titled "Selected Centers" and is composed of four chapters, each on a center where Tasso's lyric poems received a particularly large number of settings. The centers I examine are Ferrara, Mantua, Genoa, and Prague. In these chapters, I study how local literary trends and contacts with Tasso and his entourage influenced the production of Rime settings in each center. In addition, I analyze the musical settings, determining how they fit within local compositional styles. Part II is titled "Selected Poems" and is composed of three chapters that explore the musical reception of two specific poems, "Non è questa la mano" and "La bella pargoletta, " and of group of poems, the canzonettas. In these chapters I focus on the question of transmission, tracing where composers drew the texts from, and on stylistic analysis. The dissertation is accompanied by an appendix with an up-to-date list of the extant settings of Tasso's lyric poems.