What is the best book (or c.d. ) to buy to pass the U.S. Citizenship test?

There are a lot of older (such as published in 2000) editions out there. Does it matter, or are the questions still the same?

What is the best book (or c.d. ) to buy to pass the U.S. Citizenship test?
i think most of those books pretty much all have the same standard questions. In addition, the citizenship test isnt that difficult, its not a written test and if u answer the first few questions right and they get the jist that you know what ur talking about they let you off easy. but i believe most of them have the standard 100 questions which may be worded differently but are pretty much the same.