The book develops the notion of “party personnel strategies”, which are the ways in which political parties assign their elected members—their “personnel”—to serve collective organizational goals. Key party goals are to advance a policy brand and maximize seats in the legislature. We offer a theory of how assignments of members to specialized legislative committees contribute to these goals. Individual members vary in their personal attributes, such as prior occupation, gender, and local experience. Parties seek to harness the attributes of their members by assigning them to committees where members’ expertise is relevant; doing so may enhance the party’s policy brand. Under some electoral systems, parties may need to trade off the harnessing of expertise against the pursuit of seats, instead matching legislators according to electoral situation (e.g., marginality of seat) or characteristics of their constituency (e.g., population density). The book offers analysis of the extent to which parties trade of these goals by matching the attributes of their personnel and their electoral needs to the functions of the available committee seats. The analysis is based on a dataset of around 6,000 legislators across thirty-eight elections in six established parliamentary democracies with diverse electoral systems.