Landscapes and gardens have emerged as an important medium of practice in contemporary cities. Among them, this paper examines the city through the frame of gardens. This is because gardens are being reconceptualized as a medium of activity for urban residents and have become an important subject of action in urban regeneration and the creation of urban villages. From this perspective, this paper examines and proposes an "integrated garden city theory" as a landscape theory suitable for the contemporary era by focusing on the urban structure and the behavior of urban residents through the medium of gardens, as well as the process and results. This is both a process and a result of looking back at the evolution of landscape for over a century and rethinking the identity of landscape. We first examined garden city theory, noting that Ebenezer Howard and Frederick Law Olmsted's positions on the relationship between gardens and cities were not so different, and that "working and responsive landscapes" were fundamental to cities and the beginning of landscape theory. We also examine how their ideals have not been fully realized in cities over the past century, but the prototype of gardens based on traditional garden culture is now being formed in East Asian cities, and the evolution of landscape theory in response. The conclusion is that a new version of the garden concept should be reestablished as a living infrastructure in our cities, and a new garden city theory is needed to make it work. To this end, each chapter examines three arguments, as follows First, the values of gardens and East Asian garden cultures in contemporary cities are shaped by the themes of community and integrity. Second, Korean communality, represented by apartments, is expressed through gardening and requires the reconciliation of city and life and the role of landscape architecture as a specialized field to support it. Third, we examine and consider an integrated garden city theory as a theory of practice in which city-based, everyday life, and garden mediums, i.e., city, life, and garden, are organic, based on an oriental view of nature. As a result, it is confirmed that contemporary gardens and cities are looking for important elements and values that still need to be rediscovered in East Asian landscape and garden cultures. Although the proposal of an integrated garden city theory cannot guarantee the continuation of landscaping, it can be an opportunity for all fields related to cities, not just landscaping, to collaborate and consider garden cities. Through this, it is hoped that "the concept of garden and city suitable for metropolitan or dense cities, ways to spread and support garden culture based on community, evolution of landscape theory/design theory suitable for lifestyle and terrain conditions, search for sustainable/resilient garden city theory that can respond to climate change, and establishing a new role for landscape in the 21st century" will be seriously considered.