The Foreword to this special issue of Itinerario describes the historical questions that inspired the Global Sea Routes project, from which the essays in the issue derive. It then illustrates the particular sources used in the project, namely logbooks, specifically those of the English East India Company, whose characteristics and interpretation problems are briefly presented. Then, it illustrates the digital tools used in the analysis of those sources and to obtain the digital graphic and cartographic representation of the research results; and finally, it introduces each individual essay contained in the issue.