Joaquín Rodrigo is best known as the composer of one of the most popular works of music in the classical repertoire—the Concierto de Aranjuez for guitar and orchestra. Jazz great Miles Davis said of the work, “After listening to it for a couple of weeks, . . . I couldn’t get it out of my mind,� and used it as inspiration for his album Sketches of Spain. But Javier Suárez-Pajares and Walter Aaron Clark demonstrate in this musical biography that Rodrigo’s work and influence extend far beyond that singular work. Blinded in infancy, Rodrigo didn’t allow visual limitations to prevent him from pursuing his passion for music; traveling to study in Paris; connecting with a wide range of musicians, authors, and artists; and navigating the political and cultural complexities of Franco’s Spain. Though firmly grounded in the traditional music of Spain, his creative reach extended to a wide variety of styles, genres, and media. He was as versatile as he was prolific and, one hundred years after his first serious composition, remains a figure of global renown.

This Element introduces the Disambiguating Project (DP) about the units of selection. By DP, the authors mean the thesis that the expression 'units of selection' refers to at least three non-co-extensional functional concepts: interactor, replicator/reproducer/reconstitutor, and manifestor of adaptation/type-1 agent. They present each concept and demonstrate the necessity of their isolation, because each of them responds to a distinct question about the units of selection, and these distinct questions are not always posed in combination in today's biological research. They further apply the framework to the analysis of the debates concerning the Evolutionary Transitions in Individuality (ETI) and argue that the DP interprets the ETI better than any project rejecting the three meanings of 'units of selection.' Thus, they claim that the differentiation between at least these three functional concepts is fundamental to clarify some conceptual confusions in biology, which rest on the conflation of these distinct meanings.

This Element introduces the Disambiguating Project (DP) about the units of selection. By DP, the authors mean the thesis that the expression 'units of selection' refers to at least three non-co-extensional functional concepts: interactor, replicator/reproducer/reconstitutor, and manifestor of adaptation/type-1 agent. They present each concept and demonstrate the necessity of their isolation, because each of them responds to a distinct question about the units of selection, and these distinct questions are not always posed in combination in today's biological research. They further apply the framework to the analysis of the debates concerning the Evolutionary Transitions in Individuality (ETI) and argue that the DP interprets the ETI better than any project rejecting the three meanings of 'units of selection.' Thus, they claim that the differentiation between at least these three functional concepts is fundamental to clarify some conceptual confusions in biology, which rest on the conflation of these distinct meanings.