The American Taxpayer Relief Act, passed by Congress on January 1, 2013, contains many far-reaching tax provisions. In addition to extending many tax items that had expired or were due to expire, the act also made permanent many provisions of previous tax acts. The tax features of this act are too numerous to list here, but the most comprehensive description of these changes I have found is this Journal of Accountancy article.
I highly recommend you read this article or consult a qualified tax professional to assess the impact of this act on your personal situation.
