This publication is the result of a year-long dialogue between British architect David Chipperfield (born 1953) and Swiss architect Simon Kretz (born 1982). The two began working together through the Rolex Mentor and Prot g Arts Initiative, in which Chipperfield mentored the younger architect for a year. This publication focuses on a single aspect of their conversations--the problems and possibilities of planning.On Planning aims to intervene in the future of urban development, offering a manifesto for a relational, collective and diverse future for our cities. Using the Bishopsgate goods yard site in East London as a case study, Chipperfield and Kretz explore the conditions under which an ideal urban development project could flourish. The conclusions reached through this exercise demonstrate how future large-scale developments elsewhere could have more positive urban impact, both at the scale of the neighborhood and the wider metropolis.