inquiry into the distant future. Meanwhile, this volume is a succinct sur-
vey of the present state of knowledge.
I am grateful to Lynn Berat, Leonard Doob, William Foltz, Christopher
Saunders, Robert Shell, and Johann van der Vyver for valuable criticisms
of a draft of chapter 8; and to Leslie Bessant, Catherine Higgs, and Sean
Redding for comments on the first edition, which they have been using in
their university and college classes. This edition, like the first, has bene-
fited greatly from the professional skills of Charles Grench and Laura
Dooley of YaleUniversity Press.
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