The GAP document library is small enough to read in an afternoon and dense enough to repay a week. If you are new to it, start with the two declarations. The Nairobi Declaration (April 2015) is the founding text; the New York Declaration (October 2015) is where the post-Habitat III ambition first appears.

Then read the Partnerships for the New Urban Agenda consensus document, which is the intellectual centre of gravity. The plenary records and speeches around it show the argument being made in real time, to real negotiators.

For something more human, open the 58-page Media Coverage 2015-2017 e-book. It gathers the press the movement generated, and it is the closest thing GAP has to a scrapbook. Taken together, these files are a primary source on how stakeholders moved from the margins of a UN process to paragraph 128 of its outcome.