The curator of paleontology at Montana's Museum of the Rockies describes the discovery of a Tyrannosaurus rex fossil and its excavation, and explains its scientific importance. So far, only ten skeletons that are more than 30% complete have been found; this one (spotted in 1988 by a young woman hiking with her family) was the first to be nearly complete. As such, it's a source of substantial new information, especially concerning the small size and surprising strength of the animal's ``arms'' and the nature of its normal stance: head and tail in a near- horizontal line balanced above the legs, unlike the traditional museum display with head rampant and tail on the ground. Horner's lucid text, co-authored by the host of PBS's Nova program on the find, details the exacting task of excavating, preserving, and transporting the huge fossil remains; clear color photos give a lively sense of the site and the vigorous, yet meticulous, work. An attractive and informative update on a popular subject and on how real scientists learn more about it. Good select ``Resource Guide'' (lacks dates, but books are recent); rudimentary index. (Nonfiction. 7-11)
