Design competitions are used worldwide in public and private projects as a tool to optimize design and select design partners. For small and large projects alike, the quality of urban and architectural design, landscape architecture and art is sustainably improved by this orderly, fair, transparent, and professional process. Founded in 1998, [phase eins]. is one of the leading offices in Germany and worldwide for project consulting and competition management in the fields of architecture and urban development. On occasion of their 25th anniversary, the partners of [phase eins]. present the fourth volume of "The Architecture of Competitions". As in the three previous volumes, the competitions coordinated by [phase eins]. in recent years are documented with extensive illustrations and explanations: a total of 27 projects in Germany, Austria, Albania, Ukraine, Kuwait, Belgium, Canada, and Lebanon between 2016 and 2023. In addition to a brief explanation of the respective task and procedure, the submitted designs for the projects in architecture, urban design and landscape architecture are presented in comprehensive illustrations. This collection also includes several texts by the authors on fundamental issues of competitions.