When performing research in U.S. immigration law, secondary sources should be your first stop. These resources, though not generally citable, can provide essential grounding information and links to primary law.
General secondary sources in immigration law provide a broad overview in immigration topics. These sources may be quite extensive (see Gordon & Mailman, below) or concise (see Kurzban's one-volume overview.) Most of these works are available both in print at Rains Library and online via Lexis or Westlaw.