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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.

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Library of Congress Catalog Card Number 98-85699

International Standard Book Number 0-309-0608108

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Cover: Saarinen's Gateway Arch (1965) on the banks of the Mississippi River at the Jefferson National Expansion Memorial Park in St. Louis, Missouri, commemorates the westward expansion of the United States after Thomas Jefferson's purchase of the Louisiana Territory (1803) from Napoleon. St. Louis, a crossroads for the early French, British, and Spanish empires in North America, was a focal point for Mississippi River trade and a principal marshaling ground for the pioneer wagon trains setting out to the West on the Santa Fe and Oregon trails. The artist, Grace Roads (b. 1921), met her husband, Paul, in St. Louis (1944). They now reside in Lafayette, Colorado, part of the original Louisiana country comprising all the lands draining into the Mississippi—claimed in 1682 by René-Robert Cavelier, Sieur de La Salle, in the name of King Louis XIV. Mrs. Roads is the mother of John Roads, a member of the GEWEX panel.

Copyright 1998 by the National Academy of Sciences. All rights reserved.

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