The present DMA Document explores the life and work of Costa Rican composer Mario Alfagüell (born 1948) over five chapters. Chapters one to three place the composer in a historical/cultural context and chapters four and five explore the compositional approaches of the composer. Chapter one presents a historical overview of music in Central America; chapter two presents the history of academic music in Costa Rica; chapter three presents the biography of the composer; chapter four describes his compositional techniques; and chapter five presents an analysis of three piano works. This document includes two appendixes. Appendix A presents an interview with the composer and appendix B shows the music scores used for the analyses in chapter five.