Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Invaluable collection of early Brazilian jazz

Gafieira music, the lively, big band-influenced dance jazz of the pre-bossa nova nightclubs, is one of Brazil's least well-known styles, eclipsed by the suave glamour of the bossa crowd and the various waves of rock and samba crossovers that followed. Gafieiras were dancehalls, homes to dancers and dance bands, and the music fused samba and other early styles such as frevo and choro with sizzling, North American big band swing. This 2-CD set includes some of the era's best bandleaders, such as Severino Araujo, Radames Gnattali and Zacharias, along with several tracks from the Orquestra Victor Brasileira in the 1930s, when samba songs hit the mainstream. Intelligently assembled and well documented, this collection fills a major gap in the hidden history of one of the world's most fertile musical cultures. Recommended!