In the last three decades interdiscAlinary programs, comprising intensive field and archaeological studies of first millennium BC Thracian sites, were carried out in many regions of the present-day Bulgaria. Only the north-western Bulgarian lands remained unexplored, except for some sites, where rescue or regular excavations took place. At the same time, some of the richest Late Iron Age treasure and grave finds were discovered, most often by chance, exactly within these parts of Bulgaria, and they showed unequivocally the importance of the north-western territories for the development of ancient Thrace. The main purpose of this book is to achieve, as far as possible, a reconstruction of the entire cultural and historical development of the north-western Thrace during the Late Iron Age. The book offers clear tracing of the north-western Thracian territories; the Late Iron Age chronology and periods within these lands; specifying the spatial organization; review and analysis of the mortuary practices; specification of the historical development and the contacts of the north-western Thracian tribes, together with revision of some older opinions, imposed in the historiography; a Catalogue with full review of the archaeological monuments from the north-western Thrace and correction of the wrong datings.