The new Economic Growth and Tax Relief and Reconciliation Act of 2001 is full of surprises. If you die and leave stock to your children in 2010, they will have to prove what your basis in that stock is. If you bought AT&T stock in 1968, you can imagine what a nightmare that will be for them to reconstruct what your basis is in that collection of stocks that have spun off from your one purchase. The same is true for your home and other assets you have wisely invested in for the long term. The best response would be to take an inventory of your estate now, listing all of your assets, when you acquired them, and how much you paid for them. Also add in any additional money spent improving the investment. If you do not have, or cannot find, records, give a best-guest estimate, sign and date it. While the IRS may not accept such proof, if it is dated today, it will carry much more weight in 2010 than one dated then. This information will also be very useful if you decide to liquidate any of these assets during your lifetime.