This volume is the first of three in a series surveying the theory of
theta functions which play a central role in the fields of complex
analysis, algebraic geometry, number theory and most recently particle
physics. Based on lectures given by the author at the Tata Institute of
Fundamental Research in Bombay, these volumes constitute a systematic
exposition of theta functions, beginning with their historical roots as
analytic functions in one variable (Volume I), touching on some of the
beautiful ways they can be used to describe moduli spaces (Volume II),
and culminating in a methodical comparison of theta functions in
analysis, algebraic geometry, and representation theory (Volume III).
Researchers and graduate students in mathematics and physics will find
these volumes to be valuable additions to their libraries.