As said above, the book "Revolutionaries" is a collection of mostly book reviews and a few essays by Eric Hobsbawm, written in the 1960s. Written in Hobsbawm's usual accessible and lively style, he considers all sorts of topics related to socialism and revolution. The quality of the reviews/essays varies a bit, but is generally high, and there are a few gems in it. Interesting in particular are his criticism of Hannah Arendt's idealist conception of revolution, his articles on historians and communism, his piece on the May 1968 movement in France, and an essay on "the revolution and sex" (which should really be a book of its own). Less succesful are some pieces on guerrilla war and on Leninism and revisionism. A curious addition is an article on revolution and cities, in which Hobsbawm discusses the oft-remarked, but rarely thoroughly analyzed, relation between city layout and planning on the one hand and the success of riots and insurrections on the other. Nowadays with Marxist influence firmly rooted in the area of social geography as well, there is more work on this, but Hobsbawm's article is a good preview.