I have been using Citizenship - Passing the Test for years. It is the best book for low to low-intermediate English speakers. Well educated, proficient English speakers can generally prepare for the citizenship test on their own, although I doubt that they really learn very much. For those who are less proficient in English and with no exposure to American history, this is a great book. I use it in a class setting, generally one lesson a week, sometimes two a week. While the lessons are straight forward, they are a jumping off point to really teach the related American history and civics. At the end of the course my students know our American history better than a lot of people who were born and educated in the US. And they pass the test! The book is always updated as needed. I will use it again this coming year.
Edward S Faggen Volunteer ESL / Citizenship Teacher Temple Olam Tikvah Social Action Committee