This dissertation comprises three independent papers at the intersection of housing economics and public economics. Two papers—the first and third chapters—are empirical investigations of how federal policy shapes local outcomes through government-funded housing construction in the mid-twentieth century and through research funding at the turn of the twenty-first. The third paper is a theoretical contribution that develops a dynamic framework for studying housing tenure choice. Together, they examine how public investment and household decisions jointly determine the spatial organization of cities and the diffusion of knowledge within them. The first chapter examines how early American public housing affected the income and demographic composition of targeted neighborhoods. From the mid-1930s through roughly 1960, public housing combined two missions: providing decent housing to working-poor families and curbing urban decay through slum clearance. It also was the first nationwide attempt to use housing policy to limit urban poverty concentration. I construct a novel dataset with development locations and construction dates in 44 cities and use a shift-share-style instrument that exploits exogenous aggregate fluctuations in federally funded units interacted with each neighborhood's likelihood of receiving the policy conditional on its start-of-period characteristics. In neighborhoods most likely to be targeted, public housing increased the shares of families in deciles 3 through 5 by 4 to 6 percentage points each and raised average family income below the city median by about 20 percent. Targeted neighborhoods became mixed-income areas, in sharp contrast to the high poverty concentration that followed policy changes beginning in the 1960s. The second chapter develops a tractable dynamic structural model of housing tenure choice that can serve as a benchmark for analyses combining search-and-matching frictions, household heterogeneity, and dynamic decision-making. The environment features a metropolitan area with two symmetric communities, a continuum of agents with heterogeneous income, and idiosyncratic location preference shocks that generate demand for mobility. Agents choose between owner-occupied and rental housing and make consumption-savings decisions. In stationary equilibrium, agents sort into tenure based on income: households above a threshold own while those below rent, with the equilibrium house price pinned down by the marginal household's indifference condition. The model's transparency makes it suitable as a foundation for extensions incorporating credit constraints, bilateral bargaining, and mortgage lock-in effects. The third chapter, coauthored with Gautier Lenfant, asks whether large expansions of established federal research programs yield substantial returns. To answer this, we examine the NIH doubling—the dramatic increase in National Institutes of Health funding from the mid-1990s to 2003—and trace its effects on local corporate innovation. Using a shift-share difference-in-differences design comparing 64 commuting zones containing R1 universities based on their historical NIH funding exposure (1985–1995), we find that a 1 percent increase (or, on average, a $1.2 million increase) in pre-doubling funding generated approximately $0.9 million in additional yearly funding at the 10-year horizon, along with 1.1 additional research projects, 5.7 NIH-supported publications, and 1.12 additional corporate patent filings. Two channels carry knowledge from universities to firms: direct commercialization by former NIH principal investigators and indirect transfer through their research collaborators, with the indirect channel an order of magnitude larger than the direct one. Taken together, these chapters underscore the role of public policy and market structure in shaping where people live and how knowledge spreads across space. The empirical chapters quantify medium to long-run effects of two landmark federal programs, while the theoretical chapter offers a foundation for future structural work on housing markets.