Applying the descriptive (monographic) method, the author discusses the continuity and development trends of characteristic features of historical in emerging architectural style samples in modern cases in the turn of the 20th and 21st century, i.e. particular architectural objects from Riga, Latvia and across the world. Special attention was dedicated to the methods and creative techniques employed, typological specific character of objects and buildings defined by the applied materials and technologies, as well as the latest and topical criteria for classifying architectural styles. The author’s objects of interest are methods, emerging techniques, focuses, trends, fields, and concepts of an architect’s creative work in the turn of the 20th and 21st century, as well as modern architectural styles and their tendencies, i.e. the reason why an architect sees a building or object at a certain place and time in one particular way, not another. The author rather focused on researching methods and techniques employed in creative work than studying the practical ones related to technical aids. For the purpose of better understanding of modern architectural phenomena, the historical concept of style was reduced to analysing the approaches used and creative architectural methods applied in design. Thus, the author analyses and attempts to formulate the most topical guidelines and trends in the modern architectural theory. With a comprehensive range of technical, architectural engineering and technological tools being available in modern architectural practice, it is of key importance to define modern, logically comprehensible and conveniently applicable classification principles, as well as 1) establish and continuously update a system for classifying dominant architectural realms that enable to navigate; 2)comparatively analyse and evaluate, as well as 3) study and forecast phenomena in the domains of practical architecture, creative architectural work methodology, and architectural style – 4) analyse and systematize cognitive and conceptual principles and techniques, architects’ creative working methods. 5) It is also equally important to teach and learn, acquire at architecture schools and in the course of professional architects’ lifelong learning process. The existing and expanding diversity of the above mentioned fields and possibilities leaves increasingly fewer opportunities to define, classify and analyse separate objects, architectural stylistic fields, and authors themselves according to formal (constructional, technical, or compositional and visually esthetical) features, principles, attributes and elements. Instead, understanding, analysing and substantiating each author’s working methods, or methods employed for developing each separate object, that can be used to trace and assess the common and distinctive features of modern architectural styles in each particular object and in its development process and substantiation, acquires an increasingly large and important role. Some of the expected results from such transparent analysis and classification formulated and introduced by the author: simplified and enhanced learning process for architecture students through in-depth awareness and understanding of the genesis of architectural forms and conceptual principles, i.e. students’ increased ability to perceive, understand and analyse the key principles of shaping architecture and existing domains of architecture, as well as a result – a larger and increasing proportion of high quality and meaningful contemporary architecture in everyday practice.