As New York came to a halt with COVID, Michael Kimmelman composed an email to a group of architects, historians, writers, and friends, inviting them to take a walk. Wherever they liked, he wrote--preferably someplace meaningful to them, someplace that illuminated the city and what they loved about it. These intimate, funny, richly detailed conversations between Kimmelman and his companions became anchors for millions of Times readers during the pandemic. The walks unpacked the essence of urban life and its social fabric--the history, plans, laws, feats of structural engineering, architectural highlights, and everyday realities that make up a place Kimmelman calls "humanity's greatest achievement."