Moore argues that "there is a distinctively American Muslim experience which is the product of a particular social environment." To discern what this might be, she focuses on the role of U.S. civil law in Muslim lives. The subject matter of Al-Mughtaribun (Arabic for "emigrants," also a hint of a pun on the word "Westernizers,") ranges widely and includes Muslim efforts to emigrate to the United States a century ago, Muslim prisoners in American jails, "hate-crime" legislation, and attempts to build mosques in suburban areas.

Although Moore is not always a reliable guide (her political views sometimes get in the way), her subject matter is original and always interesting. She digs up what may be the first reference to Islam in the U.S. legal literature (an 1811 blasphemy case, calling it an "imposter" religion) and shows how the anti-Mormon campaign of the late nineteenth century turned polygamy into a barrier against Muslim immigration. (Indeed, the first foreign Islamic missionary to the United States, a very respectable Ahmadi who arrived in Philadelphia from Great Britain in February 1920, was straightaway incarcerated and told to return whence he came, on the grounds that he advocated polygamy; after two months in custody he was released-but only on strict condition that he not promote polygamy). The law does provide, as Moore holds, an excellent prism through which to understand the specifics of American Islam.