IT'S EASY to see why the Association of American Foreign Service Women work so hard for their annual Bookfair (today, tomorrow and Thursday through Saturday). The fair performs two essential jobs: It helps them fit into the tight State Department weight allowances and it raises money for its scholarship fund and community projects. Though I'm sympathetic to the second goal, it's the first that reaches me.

The notice reminded me, as it always does, of our experiences in the Foreign Service carrying "The History of the Hemp Industry in Kentucky" and 80 other boxes of books to three continents. And as recently as seven years ago, when it took us six days and $600 to move one block -- mostly because of the books.

In the first place, I had rescued "The History of . . . " book from the wastebasket of the Knoxville (Tenn.) News-Sentinel book editor. I know why I wanted it, though the reasons are obscure to anyone else, except (heaven be praised) my immediate family.

I wanted it because I have a magpie madness for the possession of books -- not first editions, but books: paperback, hardbound, handstitched, glued, with or without covers, pages missing or not. My husband, two daughters and mother feel exactly the same way.

Feeling like this, it was probably insane for us to go into the Foreign Service. In the seven years we'd been married, we had already accumulated more books than most small libraries, not to mention seven years of The New Yorker, Saturday Review of Literature (1949-1956), a complete set of Flair magazines (the one with the two-dimension cut-out covers), not to mention House Beautiful and House & Home magazines. Though we had no children then, our 12-room Victorian house was barely enough to hold the collection. When we left Knoxville to come to Washington and the Foreign Service, we distributed stacks to my mother and our friends.

When the time came for our first post, we panicked and sold a large stack of books to the local secondhand dealer. I remembered it covered the bottom of our station wagon several times. But then, when all of our Foreign Service friends were nervously buying American shoes and boxes of baby formula in preparation for going overseas, we prepared to go by buying a copy of the second edition of the unabridged Merriam-Webster Dictionary.

In Zurich, Switzerland, our accumulation slowed down a bit, because it wasn't as easy to buy books in English, though we did acquire the requisite number of large frightening German dictionaries.

And then came the posting to Belize, a tropical town on the Caribbean coast of British Honduras. We had a full shipment allowance, since you couldn't buy anything in Belize except large wooden bowls made from tree burls. Though it was a British colony, books were in as short supply as non-rusted needles, bananas and any tea except for Red Rose. The local library had been given to the community by a German, Baron Bliss, who never came to the colony but viewed it as it should have been, from his yacht a few miles off shore.

We stacked our magazines under the eaves for safekeeping and arranged our books artfully. And then came the hurricane -- our Flair magazines (now, I understand, worth a good bit of money), Saturday Reviews and New Yorkers were totally lost. Many other books acquired the Belize patina of mold in tropical colors. The occasional book was eaten by the wharf rats and the foot-long roaches, which no vigilance could keep from our walls.

We sunned the books, threw out the magazines (adding tears to the wetness) and bought more books.

Then the guillotine sliced through our hearts -- we were posted to Vienna, Austria, with a limited shipment. We couldn't store the books -- the designated storage place was New Orleans, where those that hadn't molded would. We sold most of our furniture (including, I am anguished to report, a complete set of Czech Thonet and a service for eight of Russell Wright china), the refrigerator, our old clothes, the baby beds and buggies (in defiance of fate). We gave away 40 boxes of books to the Baron Bliss library.

My husband built a marvelous lift van of mahogany (the only wood available), designed to become a playhouse upon arrival. Like the ark, we fitted in the irreplaceables such as our set of Dorothy Sayers, Phantasmagoria and Great Plays, planning to buy such frivolous things as wintercoats and pillows on arrival.

Coming back from Vienna, we were pared down, by our standards, because of the necessity of ordering books from England.

After a tour of duty here, my husband was posted to New Zealand. We looked at our 20-room 16th Street house with the wall-to-wall bookcases and the stacks of books in the corners awaiting the building of new bookcases, and we looked at each other. My husband resigned from the Foreign Service, went to work for the Smithsonian and kept on building bookcases.

So I was glad to hear that the AAFSW is having a bookfair. They called up and asked if we'd donate some. We said, smugly, "We'll come and buy."