Joe Day discusses some historically important diagrams--from Alfred Barr's attempts to make sense of modern art to Time magazine's family tree of hip-hop--as a preface to a discussion of his own use of diagrams. He describes the diagrams of his thesis project in the 1990s, an attempt to make sense of architectural practice in L.A. in 2002, and tracing lineages in contemporary Japanese architecture. He turns his attention from timeline diagrams to diagrams that map according to conceptual coordinates, including his own 2007 mapping of L.A. practices. Day discusses cases where the diagram generated the project, from Corbusier's Radiant City (1924) to Benjamin Constant's New Babylon in the 1960s. He presents his most recent attempt to map the most important issues at SCI-Arc with two diagrams representing a range of positions within the categories of Science and Philosophy. He concludes with the diagrams that led to his book Corrections and Collections (2013). He stresses that diagrams are not only good ways to manage large amounts of information, but, done right, explore provocative questions.