Hemingway is hot right now. So is William Faulkner, John Steinbeck, F. Scott Fitzgerald. Ten, twelve years ago, you could pick up a first edition of Fitzgerald's "The Great Gatsby," in perfect condition, its dust cover without a tear, and it might cost you $25. Today, it would be $500.

Collectibles: the idea that money invested in beer cans and movie posters and walking sticks and comic books and Corvairs and Edsels and piggy paraphernalia is better than putting it into the bank and drawing the normal rate of interest. It is what's making antique books of secondhand books. It's what's drawing crowds to book fairs, like the one in the midst of a three-day run at the Westpark Hotel in Rosslyn.

The question, of course, is whether all these collectibles, these suddenly desirables, will still be worth something 10 or 20 years from now.

Edward Myers thinks not.

Collecting is Myers' business and he thinks you could end up buying a first edition of "Gatsby" for $25 again.

Washington's Antiquarian Book Fair has a lot of things other than books. Somehow, books and letters have stretched through the logical extensions of autographs and maps to include antique prints and posters.

There is a movie poster of Universal Internationl's "Law and Order" from 1956, with Ronald Reagan, silver star on his shirt, a shotgun in his right hand, a six-gun in his left, and Dorothy Malone falling all over him, with the words across the top, "From Dodge City to Tombstone . . . his guns were the only law!" Price: $190.

There is a check that Zane Grey wrote to himself for cash back on Sept. 10, 1935. He endorsed it on the back. Two signatures for $40.

There is a picture of Teddy Roosevelt, a large portrait of him at his desk, poring over his work in the White House, which he signed on his last day in office to his vice president: "To Charles W. Fairbanks, with the hearty good wishes and regards of his friend and colleague, Theodore Roosevelt, March 3d, 1909." Price: $3,000.

Edward Myers remembers the way he felt about a copy of Mark Twain's "Tom Sawyer." It was a first edition. He read it and reread it and never wanted to part with it. He had no choice. He needed the money. He had a couple of thousand invested in it and when he had a chance to sell it for $2,500 he did it to pay the mortgage.

The night when he was browsing through the other dealers' booths and came across a copy of "The Memoirs of Sherlock Holmes," he did not rush past it. "I've had it four or five times. I'd like to own it again." He paused. "For awhile." He has grown accustomed to selling what he would love to own himself. He would not care to own a second edition or a third or any other. Just a first.

"It was printed when it was written. It's a part of history you're holding," he said. He would caress it. And care for it. And sell it, first chance. He allows himself to collect only a few naturalist books, and that's it.

"The worst thing you can do," he said, "is fall in love with what you're selling."

Christopher Jaeckel's grandfather, Walter R. Benjamin, was a reporter for Charles Dana at the New York Sun before the turn of the century. One day in 1887, the city loaded up several wagons of papers at the New York Customs Office and were taking them to the Hudson or the East River to dump. Benjamin talked them into giving him all of the papers instead. Benjamin's brother was an antiquebook dealer at the time, and he knew there could be value in a man's correspondence, if he were the right man.

What Benjamin found in those wagon-loads of papers was enough to get him started in business. Walter R. Benjamin Autographs, Inc. Walter's daughter, Mary, took over the business and continued to pore over old papers and through old trucks. Twenty years ago, a man walked in off the street to Mary Benjamin and had in his hand some legal documents he had found in a trunk in his attic. It was the original bill of sale for Flushing, N.Y., to the Indians.

Ten years ago, a man saw an old trunk at a flea market in Pennsylvania, tried to open it and couldn't, shook it and knew there were papers in it. He paid $5 for the trunk. Mary Benjamin paid $5,000 for the contents. It contained authentic letters from A. Lincoln.

To authenticate an Abraham Lincoln or George Washington is not difficult. To discern a genuine Jimmy Carter is. First, there are autopens to contend with. Then, too, it probably never occured to Lincoln to have Mary or some aide sign his papers and letters for him. He was still writing in longhand on envelopes.

Susan Clough, Carter's aide, however, can sign his name as well as he can. Joe Rubinfine, who owns the Teddy Roosevelt picture and deals in presidential signatures, says he doubts that he could tell one from the other.

Right now, it probably wouldn't matter much if it's one of Susan Clough's Jimmy Carters, or one of Jimmy Carter's Jimmy Carters. Neither is hot. A. Lincoln or a Washington, even as a cut signature -- presumably off the bottom of a letter -- will bring $750. What's hot now are dead movie stars. Bogart, Garbo, Chaplin, Monroe, Gable.

"People think of those as investments," Jaeckel says. He shakes his head. He thinks of a Bogart signature the way Edward Myers thinks of a first-edition "Gatsby." "I wouldn't waste a lot of money on them," he says. Time and tradition say some day a Jimmy Carter will be worth more than a Bogart.