I am in a class about Latin American Politics, and this book is on the reading list. There are a few events that I don't quite agree with the author on
The war of the triple alliance is mostly caused by the British being angry about Paraguay trying to avoid capitalism.
Panama is an entirely invented state to steal the canal
And so on. I do not wish to discredit a book that I do not fully understand, however, it reads more like propoganda than history to me.
I know this is a bit late, but I saw this and thought I would give a response. So, for point 1, certainly the British desire to open up Paraguay was a key factor in their involvement, however, Paraguay (see Armies of the War of the Triple Alliance 1864–70: Paraguay, Brazil, Uruguay & Argentina by Gabrielle Esposito) was lead by the jingoist/expansionist Francisco Solano López and at the time held the largest river navy in the region - which frightened its neighbors. The war kicked off when Paraguay attempted to exert authority over Uruguay - at least that is from this particular perspective. The other of course being that mentioned in Open Veins; British interests.
The second point, is a matter of perspective again. On one hand it belittles the Panamanian people by denying them historical agency as a nation. Though, on the other hand, it would be equally inappropriate to deny any machinations on the part of the US.
Something interesting to note is that the author - Eduardo Galeano - has himself disowned the work. His comments in this NY Times article are worth the read http://www.nytimes.com/2014/05/24/books/eduardo-galeano-disavows-his-book-the-open-veins.html