How do individual legislators in the European Parliament (EP) make decisions on the wide variety of policy proposals they routinely confront? Despite a flourishing literature on the European Union's only directly elected institution, we know surprisingly little about the micro-foundations of EP politics. Who Decides, and How? seeks to address this shortcoming by examining how individual legislators make policy choices, how these choices are aggregated, and what role parties and committees play in this process. It argues that members of the EP lack adequate resources to make equally informed...