The Brazilian Sound: Samba, Bossa Nova and the Popular Music of Brazil, by Chris McGowan and Ricardo Pessanha, has been the leading introduction to Brazilian music in English since it was first published in 1991. It has been translated into Japanese, Korean, German and French. A third print edition was published by Temple University Press in 2008 and an updated online version from 2014 is available in the Kindle format worldwide through Amazon.com. More info: thebraziliansound.blogspot.com.
Also, The Brazilian Music Book, a collection of interviews with Antonio Carlos Jobim, Dori Caymmi, Djavan, Airto, Laurindo Almeida, Carlos Lyra, Lenine, Gilberto Gil, Luciana Souza and others, can be accessed here: brazilianmusicbook.blogspot.com.