A great deal of new quantitative research has been produced over the last three decades which has radically changed the received interpretation of Italian economic development. Against this backdrop, the Bank of Italy, Istat and the University of Rome "Tor Vergata", together with academics from other institutions, developed a project to estimate a new historical national accounts time series. The reconstruction covers the 150 years following the political unification of Italy and is based on the most up-to-date results in the literature. It provides estimates of supply and uses at constant and at current prices. In this chapter a general picture of the new time series is drawn. Historically significant periods are taken into consideration, using them as case studies in order to illustrate some features of the new data, both technical and substantial. A detailed methodological account is given in the appendices.