Development of the Grammatical System of the Baltis Languages (in Lithuanian) The author goes closest to his teacher Vytautas Maziulis, who in his turn develops principles first introduced in Baltic linguistics by Jonas Kazlauskas. Nevertheless the author essentially differs from his Lithuanian colleagues in two points: a) all ideas are included in the field of the contensive typology of languages and on this basis the whole picture of the development of the Baltic languages is depicted; b) many ideas are verified by external comparison with non-Indoeuropean languages. In the PREFACE to the book a short notice of its typological statements is given and a role of Vytautas Maziulis in creating theory of Baltic and Indoeuropean declension is emphasised. After that the author elucidates terms which are constanly used by him but are not used by his Lithuanian colleagues. Further GOALS AND METHODS of the book are discussed: 1) to present historical development of the Baltic grammatical system as a result of changing language structure from its Indoeuropean stage of the "Active" typology to the stage of the "Accusative" typology; 2) to do this on the basis of the inner reconstruction and typological verification. Among the MAIN CONCEPTS of the book especial attention is to be paid to the concept of the grammatical category of version, to crucial distinction between the lexical-syntactical category of class and the morphosyntactical category of gender, to the author's treatment of the concepts of language and dialect. PART I sets forth the author's view of Baltic as of the last manifestation of Common Indoeuropean on the basis of the newest concept of the parent language as of in space and time wandering zone of minimum innovations. In this part are discussed: a) the author's concept of the Indoeuropean vowel-gradation, viewed morphonologically (this is essential to understand origin of the Baltic declension), b) inherited integrant features of Baltic and Germanic languages paying attention to the class of preterital-present verbs (this is essential to understand origin of the Baltic conjugation). PART II deals with the history of the Baltic noun. Here the development of the nominal and pronominal declension in Lithuanian, Latvian and Old Prussian is discussed on the basis of distinction between four Baltic paradigmatic cases and several adverbial non-paradigmatic cases (the theory of V.Maziulis). The idea of later development of pronominal paradigms is set forth by the author once again after the pause of 20 years. For the first time the author summarises here his principles of Prussian reconstructions. PART III deals with the history of the Baltic verb. It begins with the SEMANTICAL CLASSIFICATION of the verbal STEMS, and is carried out for Lithuanian, Latvian and Old Prussian. On the basis of the analysis of the paradigmatical and syntagmatical relations (11 distinctive features chosen) and semantical neutralization in formal classes of Baltic stems, semantical classes of the Baltic verbal stems are identified. The said analysis is later used to specify history of some verbal stems in separate Baltic languages. Historical analysis begins with identifying PRETERITAL-PRESENT verbs in Baltic. Further the PRE-INFINITIVE period as well as expression of the 3rd PERSON are touched upon. The book ends setting forth a concept of FORMATION OF VERBAL PARADIGMS finishing the intemediate stage of verbal ATEMPORALITY. The book is supplemented with annexes of which the STRUCTURAL INDEX OF BALTIC VERBS is mostly significant while presenting results of formal and semantical classification of verbal stems in Lithuanian, Latvian and Old Prussian (every verb is given with ist numbers in corresponding formal and semantical classes).