This thesis uses causal diagrams to describe and quantify the associations between social conditions - such as wealth, education and occupation; proximal health risks - in particular indoor air pollution from solid fuel use; and acute lower respiratory infections (ALRI) among African children. The aim is to delineate different pathways that translate lower socio-economic status into poorer health outcomes. A conceptual causal diagram is used to org?????????????anise a 'series of a priori hypotheses, which are operationalised and tested using Demographic and Health Survey data for Benin, Ethiopia, Kenya and Namibia and, for the solid fuel use pathway, a pooled set of World Health Survey data for sixteen African countries. In doing so, this thesis employs a variety of statistical techniques, including cluster analysis, logistic and ordered logistic regression, survival analysis and Bayesian multileyel and spatial modelling. ?????????????The results suggest that solid fuel use across sub-Saharan Africa is particularly strongly structured by wealth, maternal education and, to a lesser extent, paternal education as partially independent determinants. Heterogeneity at community and districtlevels'strongly influences fuel choice; in some countries this variation is spatially structured~With an'adjusted hazard ratio of 2.35 (1.22; .4.52) cooking with solid fuels is confirmed as a major risk for ALRI mortality. However, socio-economic gradients in ALRI mortality are weak, and are not primarily mediated' by smoke-producing cooking practices. Instead, across much of the social spectrum indoor air pollution appears to exert its effect on child health largely independently of p6~erty;~rlack of education. This thesis illustrates how the rigorous application of causal diagrams combined with standard statistical methods can characterise a complex web of interactions between distal and proximal causes of disease. The ALRI mortality risk associated with traditional fuel use points to a large potential for preventive interventions to reduce c::h.i1d. mor~!d.itY-and mortality.Imperial Users onl