A lexicon of Greek and Latin Historiography is not only meant to be an aid to reading ancient historiographical texts, which are very numerous though often fragmentary, but also represents a way of interpreting ancient historiography itself, highlighting conceptual and lexical connections (and divergences) among different texts and authors and among successive historical periods. The Lexicon historiographicum Graecum & Latinum, of which three volumes have been published (I, 2nd ed. 2007; II, 2007; III, 2015), is conceived as an alphabetically ordered repertory of all terms significant to the historian’s work. Linguistically and conceptually related lemmas are grouped together, with frequent cross-references from secondary to primary lemmas. Programmatic and methodological aspects are taken into account (vocabulary of knowledge, inquiry, verification, statement of purpose; besides, memory and selection); the historian’s attitude and animus (such as the words for polemic and criticism); his/her relationship with the recipient of the work (lexicon of communication and ‘publication’); and the formal aspects of his/her product (partitions of the work, genres and subgenres). Forty-five top scholars, both Italian and international, contribute to the work.