Complex sentence: The Foco theory of revolutionary guerrilla tactics was introduced by Marxist revolutionary Che Guevara (1928-1967) in his manual on guerrilla warfare which remains one of the classic dissertations on this subject more than half a century after its writing.
Split into simpler sentences: The Foco theory of revolutionary guerrilla tactics was introduced by Marxist revolutionary Che Guevara (1928-1967). It was introduced in his manual on guerrilla warfare which remains one of the classic dissertations on this subject more than half a century after its writing.