For once: an exhibit where you can take the time to look at every item. There are only 38 of them.

And the catalogue is 276 pages long.

The "Islamic Metalwork" show that just opened at the Freer, continuing through Jan. 5, is a first for that gallery and a fascinating rarity in any museum, for it examines the works in fine technical detail, from the way they were made to the composition of the metals they use.

Look at the 17th-century knife made for Jahangir, a Mughal ruler. It has the clean, spare lines of a modern Solingen knife, but its steel handle is delicately inlaid with gold tracery, and there are incised gold streaks down its patterned blade.

The inscription tells us the knife was forged from "lightning iron," a meteorite that fell on a village in the Punjab on April 10, 1621. Five pages in the catalogue give the story, with pictures of the exquisite handle carvings, photomicrographs of the layered blade and X-ray fluorescence analysis that shows some layers contain unusual amounts of nickel -- indicating meteoritic iron -- while others do not.

Close by, in an old painting, you come upon a portrait of Jahangir actually wearing the knife. By this time you feel you know the weapon even better than he did. It has become yours in the way precious objects belong to the curators who know their every scratch.

A foot-long brass pen box from Bukhara, made by the engraver Shazi in 1210, is magnificently inlaid with silver and copper: Arabic inscriptions honoring grand vizier Majd al-Mulk al-Muzaffar.

Calligraphy has always been a major element in Arabic art, to a degree that even western medieval manuscript illuminators never aspired. On the side of this box, for example, the letters become abstract human figures, each with a tiny face whose expressive cartoon features recall sophisticated New Yorker drawings of the '20s.

The touch of humor is a surprise.

Technical notes: "The general appearance of the pen box might lead one to assume that the box was made from metal sheet. Yet an examination of the pen box surprisingly reveals a cast structure. No seams or solder are apparent where the horizontal surfaces meet the verticals . . . In areas where the inlay has been lost, one can see tool marks, which indicate that the depression was cut or chiseled out; the depression is slightly undercut at the edges so that the inlay may be fit in securely . . ."

Enlarged photos show these details, bringing us right into the work, letting us see the hairline gouges made by the artist, whose eyesight must have been something wondrous.

Perhaps even more astonishing are some small plaques cut from forged steel by 16th-century Iranian artisans. One rectangle, about 3 by 10 inches, contains woven into filigree the inscription, "O Reviver of the dead. Accord your protection to the prince. Verily how excellent the Reviver." Thought to have been used on a mausoleum, the plaque is a fragment of a larger piece.

Hundreds of fretwork openings have been drilled, sawed and filed to create a dazzling pattern. Close to it is a medallion not two inches in diameter, overlaid with gold, whose lovely swooping curlicues say, "In the name of God, the Compassionate, the Merciful."

"X-radiography reveals fine cross-hatched scratches on the surface of the iron underneath the gold; the gold was hammered onto the cross-hatching to secure it," comments the highly readable catalogue by Esin Atil, W.T. Chase and Paul Jett of the Freer's Technical Laboratory, who spent a year and a half on the project. Research was begun in the 1940s under the late Richard Ettinghausen, a Freer curator for 23 years. Atil continued the work as curator until 1982.

The eight-lobed mandala-like plaque, apparently designed to be nailed to furniture or a wall, must have taken two months to make, according to Glenn Lowry, the museum's present curator of Near Eastern art and the organizer of the exhibit. Objects and catalogue together give one a rare glimpse of a working research museum. One 12th-century silver urn, possibly a rose-water sprinkler, had been smashed to pieces and repaired with solder before the museum bought it in 1950. Conservators picked away the heavy solder, leaving the urn in shards of silver only one-fifth of a millimeter thick in places. It was then restored, the joints virtually invisible.

Even for those who are not particularly excited by Islamic art, this little jewel of a show -- and its catalogue -- will reward a long, leisurely look.