Cities are full of contradictions. They are inspiring and exhausting, innovative and conservative, inclusive and polarizing. They are places of acceleration and change, but can also stagnate and freeze. Cities are made of steel, concrete, and glass, but even more so from the people who live in them and whose needs the urban system must address. How does it all connect? "City as a System" examines ten urban action areas - from digital transformation to urban retail, urban logistics, city politics, and housing in the city of tomorrow - and investigates the relationships and interactions between these different fields. The authors explore profound changes, challenges, and opportunities - as a pointed inventory and an entry into deeper analyses.