The ides of April are nearly here, so the time is ripe for new battle plans to outwit the Internal Revenue Service. The current offering seems to have a lot going for it. Paul Strassels spent five years as a tax law specialist in the IRS National Office here. Sylvia Porter call this book "a spellbinder" on the back cover -- and if you buy it you can take a deduction for what you paid.

The authors take the stand that the U.S. income tax system is really a war, with the IRS using every weapon it can devise to intimidate the taxpayer enemy (the "t/p," as he's called around headquarters) into "voluntary compliance" -- confessing his true wealth and paying what he owes. The stakes are high. If as few as 10 percent of us refused to "comply," the government's cash flow could collapse.

In telling us what we "need to know," there is much that the authors don't tell about the IRS -- such as how it's set up and how it got the way it is -- but they've made a real effort to compile a practical guide to the way tax returns are handled and what makes the IRS computer flag a return for a possible audit.

We explore the arcane world of TCMP -- the Taxpayer Compliance Measurement Program -- a detailed statistical sampling of 40,000 to 42,000 taxpayers to establish "normal" deduction patterns for various parts of the country and for various income levels and professions. The resulting composite profile winds up to the dread IRS computer in Martinsburg, W.Va., and your return will be measured the norm, as IRS human will check your return to see if it's worth auditing. They haven't the manpower to waste any time.

If your strength holds, the authors will walk you through a hypothetical tax return, listing deductions you're likely to get away with -- and the ones that lead to grief. Deductions for a home office start the red lights flashing; so do tax shelters. IRS has two people at the National Office who do nothing but sift through tax shelters, sniffing out the phonies. Doctors, dentists, airline pilots, artists and writers are prime audit targets. They have a rep for quirky spending habits and vague bookkeeping. It also pays to stay alive. IRS likes to audit several years of returns when people die.

If you are audited, the book supplies a firm game plan, from what to wear (same as usual) to what documents to bring in. (Don't hand the checkbook over, they advise. "May as well toss yourself into a pool with a shark.") They tell you what the auditor has been trained to look for, and how his mind is likely to work -- and warn you that "he" could turn out to be a "she."

A final chapter outlines the kind of professional help you can get, and what it's likely to cost -- from commercial preparers who "fill in the lines, taking the informtion you give them and putting it where it belongs," to independent preparers, who are often IRS alumni, and "tend to know what they're doing, but . . . they do it as if they were still in the IRS." Higher up the scale come the accountants and CPA's. ("At this level, you're beginning to take your money seriously") and a rather specialized group called enrolled agents, who have passed a "truly thorough, difficult exam" given by the IRS.

Aside from its practical advice, there is a certain ambivalence to the book. It portrays the IRS as a menacing and monolithic structure, interpreting the tax laws in ways that "verge on the mystical" amd create the impression that it is a "a separate and sovereign government." Yet Strassels has warm memories of his years in "the Service," and salutes the professional standards of the people he worked with. They are as outnumbered as the British at Balacava when the annual tax war begins; they are shunned at cocktail parties if they ever reveal where they work. But they care about what they do and love to talk shop at lunch. And the bosses make out their secretaries' tax returns.

The authors make the point, although not as strongly as they should, that in the big picture the IRS and the crazy Catch-22 collection of tax laws it administers are creations of Congress -- the folks we pay for on our tax returns. So as we wail and kick the stairs on April 15, we have only ourselves to blame.