This volume constitutes the edition of the more than one hundred letters sent by Rodolfo Lanciani to Giovanni Battista de Rossi between 1866-1894; This precious corpus of correspondence offers the opportunity to investigate the professional and human relationship between two ‘giants’ of culture in the complex plots of the immediately pre- and post-unification years and to shed further light on those fortunate decades of the second half of the 19th century in which archaeology in Rome had played a leading role, configuring, thanks to figures of the highest level and undisputed authority such as the two scholars, a solid and profoundly renewed methodology of research and processing of historical data.