"TheCityAsAHouse" is a visually stunning art book that challenges the concept of the private home. In this experiment, a 30-year-old European lives in Tokyo without a private home, relying only on a smartphone. Traditional private spaces such as bedrooms, kitchens, and bathrooms are abolished, and public spaces become the norm for daily needs. The book explores the implications of the shift of privacy to non-domestic spaces and asks whether a new form of nomadic living is emerging. It also explores the potential for new artistic and architectural possibilities and infrastructure for society. The book includes various types of data collected during the experiment and offers a digital journey through the game experiences to discover new perspectives. "TheCityAsAHouse invites readers to reflect on the future of society and living without traditional homes, and encourages them to embrace the possibilities that lie ahead.