Agustin Barrios's guitar music has become increasingly popular over the last forty years. After his death, a revival of interest in his compositions began in the 1970s, motivated by a series of publications and recordings of his music by important guitar performers at that time. The most important of these recordings came from the Australian guitar performer John Williams, who was interviewed in 1976 by ABC Television Australia for a film about the Paraguayan composer. The next year, Williams recorded a collection of fifteen works in his album John Williams-Barrios: John Williams Plays the Music of Agustín Barrios Mangoré. After this, the published editions of Barrios's works have proliferated, many of these transcriptions of the composer's own recordings. However, the publication of differing transcriptions has led to a lack of authoritative editions, creating a confusing situation for performers. Therefore, this research intends to highlight the importance of making critical editions of Barrios's works based on folk music, using the Cueca as an example. This research offers an analysis and comparison of Chilean cuecas from the first half of the twentieth-century--the timeframe in which Barrios was in contact with this genre--to Barrios's Cueca. Second, it proposes a critical/performance edition of Barrios's work taking into account both the performance practice of traditional Chilean cuecas, and the two primary sources of this work: a handwritten manuscript and the composer's own recording. This research does not analyze nor compares the Argentinian and Bolivian versions of the cueca.