In the book Keskustelupuisto / Conversation park we describe a unique artistic experiment of transforming an abandoned plot of land into a public park in the Finnish town of Rauma. In 2019 thirty residents between the ages of 6 and 89 became players in a two-year-long “Public Space Game”. Their mission was to turn 30 different visions into an urban park in 6 game moves. The park was opened in 2020. In the book we describe our original intentions when designing the game and share insights we gained while working on Keskustelupuisto for 4 years. The book touches on many questions with regards to engaging citizens in designing urban public spaces. It is an attempt to open-source the Conversation Park project so that it can be analysed, modified, and replicated. It is an invitation to learn together with the us and the participants about the many factors which have to be considered when designing a participatory project – whether it takes place in art, urban planning or politics. The Finnish edition of the book will be launched 29 March, the date for the English edition to be announced. The book is published in collaboration with Lönnström Art Museum, Rauma, Finland.