For children, missions mysterious and hands-on

With pluck and camels, the indomitable Miss Sands travels from Cairo to Nubia, filling the journal with sketches, notes, photos, and little artifacts such as a ''Small Sample of Mummy Cloth" (which you can feel) and a small dictionary of hieroglyphics. Two months after setting forth, Miss Sand reaches Biga and, very likely, the tomb of Osiris, the object of the expedition. But we'll never know. As they are about to make the archeological find of the century, Miss Sands and the rest of the party receive an ominous warning. Here, abruptly, the journal stops, and a few odd reddish spots adorn the last page.

A brief and obviously joking note at the back tells us that there's scant evidence for the journal's truth and that we should enjoy it ''as it stands." That's not hard to do.

On a more sober note, ponder this:

Who killed Cock Robin? ''I," said the sparrow, ''With my bow and arrow." . . . Who caught his blood? ''I," said the fish, ''With my little dish."

How in the world does so much grisly nursery lore embed itself in the memory of the human race? Who knows? And what to make of this antique and anonymous verse, which begins with a murder and proceeds from a confession by the sparrow, right on to a burial and protracted mourning for the deceased, each task assumed by a different bird or beast? The rapid entrances of successive characters, line by line, beg for illustration. In Etienne Delessert's stunning version of ''Who Killed Cock Robin?," handsomely designed by the artist's wife, Rita Marshall, the pages burst with a surreal and visionary panorama of large-beaked birds, owls, moon, insects, fish, and that poor, arrow-pierced robin, stiff and glassy-eyed.

Yes, this retelling could be frightening -- in the same way, perhaps, as John Tenniel's illustrations for ''Alice's Adventures in Wonderland" are frightening. Still, discomfort notwithstanding, the haunting words combined with the stunning illustrations make this a treasure and a keeper -- however odd.