The Pursuit of Italy by David Gilmour is an extraordinary book by one of the UK's great authors; and if you are only half interested in what made Italy (eventually) into a nation state (it is celebrating its 150th year, this year) then this is the book for you.
As someone who visits Italy regularly (twice this year) I couldn't put it down; it is so readably and so full of nuggets and joy. Go read.