angers stifle raging forest fires by starting controlled fires of their own. Physicians create antibodies to prevent disease by using a weakened form of the virus that causes the disease itself.

And you can use taxes you already have paid to sometimes save you from further taxes. This column will show you how.

Some taxes are deductible. While federal income taxes themselves are not deductible, you may deduct state and local taxes on your income tax return.

It's all a matter of timing. You can actually lower your total overall tax bill by paying other taxes in advance. Use the government's own rules to reduce your liability. Here's how:

Remember that taxes are deductible in the year they're paid. For example, if I pay taxes due last year in this year, they're deductible this year. This opens the door to "right time" strategies and techniques. State and local income taxes are deductible.

My fourth quarter estimated payment to the state is due Jan. 15 of the following year (for example, fourth quarter 1997 taxes were due Jan. 15, 1998). By accelerating the payment by 15 days and paying that estimate on Dec. 31, I can accelerate the deduction by a whole year.

If I pay an estimated tax of $1,000 per quarter and I'm in the 31 percent bracket, this saves me $310 in taxes for that previous year. While the actual savings are realized only in the first year, this technique creates a $310 interest-free loan from the IRS.

If you don't pay estimated taxes, ask your employer to "over-withhold" your state income taxes on your last paycheck. (Make sure you have enough other money for living expenses first.) This will create the same deduction and the same interest-free loan savings.

If you over-withhold, you'll probably get a state tax refund in the next year. Any refunds of taxes deducted in the prior year are taxable in the subsequent year of receipt. This is because you over-deducted in the earlier year. But this isn't necessarily a sound financial strategy. The tables are now turned if you have too much withheld and you are, in essence, giving Uncle Sam an interest-free loan. The trick is to ensure that any "extra taxes" you pay the state equates to taxes you would have paid the federal government. Otherwise, that earlier year's deduction, unless your bracket has increased, is clearly more valuable than the later year's inclusion. If my bracket isn't going up, I would always much rather have the money now than in the future.

The same concept works with real estate taxes. I pay my real estate taxes directly. My fourth-quarter real estate taxes are due Feb. 1 of the next year. By accelerating the payment to Dec. 31 of the previous year, I again create a first-year immediate tax savings and another interest-free loan from the IRS.

Now that you know the concept for tax minimization, let's look at what taxes are actually deductible.

In addition to state and local income taxes, you may also deduct amounts withheld from your wages for certain state disability benefit funds and any state unemployment fund as taxes. Contributions to private disability plans, however, are not deductible as taxes. (Private disability insurance premiums may be deducted as medical expenses, but I usually don't advise doing so. If you took the tax deduction, and become disabled, all payments would be taxable. If you never took the deduction, all payments would typically be tax-free.)

Foreign taxes are those imposed by a foreign country, a U.S. possession, or any of its subdivisions. Foreign taxes that you pay can either be deducted as an itemized deduction or claimed as a credit against your U.S. tax. While for most people the credit is usually better than the deduction, certain foreign tax credit reductions or alternative minimum tax limitations may weigh in favor of the deduction.

Estate, inheritance and other wealth-transfer taxes are usually not deductible.

Real estate taxes also are deductible. There are many state, local or foreign taxes on real estate levied for the general public welfare. Local benefit taxes are deductible if they are for maintenance or repair, or for interest charges related to these benefits.

Property taxes do not include specifically itemized homeowners' association dues or trash collection fees (these fees are deductible if not separately stated and are just part of your general property tax).

However, if you're a tenant shareholder in a co-op, you may deduct the amounts you pay the corporation that represents your share of the real estate taxes on the property. If you own a condominium, the real estate taxes you pay on that property are also deductible.

Note that if you and your spouse hold the property jointly and file separate tax returns, each of you may only deduct the taxes you individually paid on the property.

If real estate is sold during the year, the real estate taxes must be divided between the buyer and the seller according to the number of days that each party owns the property. The seller pays the tax up to the date of the sale and the buyer pays the tax, starting with the day of the sale. If you bought or sold property during the year, don't forget to deduct those taxes paid and reported at closing on your closing statement. If you financed your home, your end-of-year bank statement typically would not include those taxes.

Personal property taxes are deductible too. But they are subject to certain requirements:

Small savings are cumulative and add up to greater financial independence.