Don't ask. Don't tell.

That's how many American families approach the subject of inheritance.

Grown children, fearing they'll look greedy and insensitive, don't ask. Their parents, reared when discussions of money were taboo, aren't about to tell.

So why broach the subject at all?

Well, because death is final. Many financial mistakes and emotional traumas can be avoided with plain talk and planning.

Parents of the baby boomers are expected to leave 115 million bequests worth more than $10 trillion, in 1989 dollars, between 1993 and 2040, according to a 1993 Cornell University study.

The vast majority will come from the nation's wealthiest 10% of families. Middle-class parents, however, can easily leave estates of $1 million or more, due to the increase in stock values in the 1990s and the recent run-up in real estate prices.

Without a will or a trust, the assets from the estate will be distributed according to state law, not necessarily the wishes of the deceased. Yet even parents with large estates or family-owned businesses often do little or no estate planning.

Such avoidance can be costly.

Currently an individual can leave an estate with up to $1.5 million worth of assets -- such as stocks, real estate, IRAs and life insurance -- free of federal estate tax, but any amount over that is taxed at a rate as high as 48%. But one spouse can leave an unlimited amount tax free to the other spouse, whose estate will later be subject to IRS limits. (See chart for future changes in the estate tax exemption.)

With good estate planning, though, parents can leave much more to their heirs and to charity -- not to Uncle Sam -- by employing trusts, family limited partnerships, life insurance, charitable giving and annual gifts.