Lorie Shaull, Voting in Washington, DC, 2016 (Source: Wikimedia Commons, CC2.0)
Literature reviews are a particularly useful resource when doing research. They address the issues involved in a specific question and the debates among scholars. They map out the intellectual terrain succinctly and give you the major landmarks in terms of key authors and significant titles for greater understanding.
A few examples are listed below. Search in both the Annual Reviews and Oxford Bibliographies Online to find literature reviews that address your political questions.