How does the mood change in Twenty Love Poems and a Song of Despair?

In Twenty Love Poems and a Song of Despair, the mood undergoes a distinct progression as the collection unfolds. The work begins with an intense focus on sensual passion, reflecting the poet's memories of past romantic affairs.1

As the verses progress, this initial intensity gradually slackens, shifting into a tone characterized by melancholy and emotional detachment. This trajectory culminates in the final piece, "A Song of Despair," which abandons the earlier romantic fervor for a mood that is profoundly bitter and hopeless. Overall, the collection is noted for being tender, sensuous, and passionate, serving as a reflection of the Chilean poet's own passionate love life during his youth.12