The study of Alzheimer's disease (AD) in the Framingham Heart Study (FHS), a multi-generational, community-based population study, began nearly four decades ago. In this overview, we highlight findings from seven prior publications that examined lifetime risk estimates for AD, environmental risk factors for AD, circulating and imaging markers of aging-related brain injury, and explorations on the genetics underlying AD. First, we describe estimations of the lifetime risk of AD. These estimates are distinguished from other measures of disease burden and have substantial public health implications. We then describe prospective studies of environmental AD risk factors: one examined the association between plasma levels of omega-3 fatty-acid and risk of incident AD, the other explored the association of diabetes to this risk in subsamples with specific characteristics. With evidence of inflammation as an underlying mechanism, we also describe findings from a study that compared the effects of serum cytokines and spontaneous production of peripheral blood mononuclear cell cytokines on AD risk. Investigating AD related endophenotypes increases sensitivity in identifying risk factors and can be used to explore pathophysiologic pathways between a risk factor and the disease. We describe findings of an association between large volume of white matter hyperintensities and a specific pattern of cognitive deficits in non-demented participants. Finally, we summarize our findings from two genetic studies: The first used genome-wide association (GWA) and family-based association methods to explore the genetic basis of cognitive and structural brain traits. The second is a large meta-analysis GWA study of AD, in which novel loci of AD susceptibility were found. Together, these findings demonstrate the FHS multi-directional efforts in investigating dementia and AD.