This is a really enormous question, for which there is no simple or easy reply. If you look just at Garibaldi, his aims are, at one level, relatively simple, but at the same time are really complex. His methods are again complex in the extreme, whilst appearing to be really simple. Similarly Cavour's aims are obscure, beyond ensuring that the King of Piedmont got the best possible deal. His methods are similarly obscure! I would suggest that, if you've not read anything yet, that you try this as an introduction http://www.amazon.co.uk/The-Unification-Italy-1815-History/dp/0340907010/ref=sr_1_4?ie=UTF8&qid=1415395699&sr=8-4&keywords=Italy+History+AS