This edition, like its companions Thucydides ll and IV, is intended primarily for undergraduates and candidates taking A-level examinations. It will also be useful to students who are approaching a book of Thucydides for the first time, or studying the Peloponnesian War from a more general, historical perspective. The text and notes are those of B.C. Marchant, originally published in 1905. A recent introduction by Thomas Wiedemann takes account of the questions which students today will want to ask about Thucydides' history, and of the present state of research; it also covers the context and aims of the work and giving essential background to the events described.. There is also a list of essential dates and a recent bibliography (1993), in which a primary criterion for inclusion bas been accessibility to the non-academic English reader.