Read an essay on the history of Orthodox Judaism in America adapted from the American Jewish Desk Reference: The Ultimate One Volume Reference to the Jewish Experience in America and posted at the MyJewishLearning.com Web site.

Read an essay by Michael Kress, editor in chief of MyJewishLearning.com, about the factions and tensions within the Orthodox movement.

Read a Nov. 27, 2012, article from The Jewish Week about how Orthodox Jews voted in the 2012 presidential election.

Read a Dec. 15, 2011, article from The Huffington Post about the Orthodox Jewish vote in the 2012 elections.

Read an Aug. 3, 2006, Washington Post story on the growing receptiveness of Orthodox Judaism to Republican politics.

The Berman Jewish DataBank has links to the National Jewish Population Study and several other studies, some of which provide different figures for the overall Jewish population.

Read the National Jewish Population Survey’s reports on geographic differences among Jews around America. The NJPS showed that although the Orthodox influence is felt nationally, Orthodox Jews are concentrated in urban Northeast areas to a greater degree than other Jews.

Eliezer Segal, a professor of religious studies at the University of Calgary, has a Web page explaining the “Varieties of Orthodox Judaism.” The page sets out the many branches of the movement.

The Association for the Social Scientific Study of Jewry describes itself as “a cross-disciplinary organization of individuals whose research concerns the Jewish people throughout the world.” The association is a valuable resource for experts and the latest research. Steven M. Cohen is the president.