THIS IS an undisguised plug for one of the best publications we've seen on the District of Columbia -- its history, its complicated system of government, things to do here and answers to those questions people are always too embarrassed to asked because they think everybody else already knows. It's a bargain booklet ($2.50 to $4 a copy, depending on the order) just published by the D.C. League of Women Voters. Not only is it an impressive research effort, but the handbook -- "Know the District of Columbia" -- is a graphically attractive and clearly written compendium, organized for ready reference.

With ofjectivity and up-to-date information, the book begins with a fact-filled portrait of the city -- who lives here, what they do and what kinds of neighborhoods they live in and how various development efforts are affecting the economy. On one page, there is an at-a-glance box of "historical highlights" that begins in 1787, with Article I, Section 8 of the U.S. Constitution -- that's the one providing for a seat of government and "exclusive" legislative powers of Congress over the District -- and goes to the election of Mayor Barry and Council Chairman Arrington Dixon in 1978.

One of the most valuable chapters is an explanation of how the congressional/local relationships work, how they evolved, how the budget is put together and enacted and how bills become law. Other run-downs included guides to the courts, the advisory neighborhood commissions, public schools, Metro, voter information and regional organizations.

We're told that many local businesses and civic organizations are already starting to snap up copies. They should. So should the city schools, where the store of local history and information on the classroom shelves has always been woefully thin.