The published parts of the General Volume, as well as the concept for the development of Part IV. Morphology, have laid down basic principles: The Bulgarian language at the dialect level is presented in its entirety – the entire linguistic territory within and outside the borders of Bulgaria is covered, where the Bulgarian language is spoken or has been spoken. Such atlases are created once in the history of linguistics, and with the printing of the BDA, Bulgarian science fits into the rich European tradition of creating similar national atlases. Unlike other studies in the dialectological literature, which are dedicated only to certain endings or forms in individual dialects or areas, in the General Volume of the Atlas, the system of the Bulgarian language at the dialect level is presented through the methods of linguistic geography, i.e. the spatial model of the Bulgarian language is given. The Old Bulgarian structure of our language is shown, with archaic forms preserved to this day in Bulgarian dialects being brought to the forefront. The summary volume also presents the temporal projection of the Bulgarian language, it is the history of the language plotted on the maps. The linguistic features mapped on the same map, preserved in the speeches from different historical periods of the development of the language, make it possible to see not only the spatial, but also the temporal projection of the Bulgarian language, or, as is known in the theory of linguogeography – to present the diachrony unfolded in space. Avanesov defines the private dialect systems and their elements varying over the language territory as the history of the language in its spatial projection. The atlas covers the linguistic phenomena relevant to the classification and typology of dialects. The accurate and precise picture of the dialect features over the entire language territory makes it possible to draw conclusions and provide answers to a number of basic questions of Bulgarian dialectology, discussed for years.