For many years all three of us have been interested in, and have tried to make contributions
to, derivative-free optimization. Our motivation for writing this book resulted from
various circumstances. We had the opportunity to work closely with the leading contributors
to the field, including especially John Dennis, Michael Powell, Philippe Toint, and
Virginia Torczon. We had some knowledge of various facets of the recent developments in
the area, and yet felt there was a need for a unified view, and we hoped thereby to gain a
better understanding of the field. In addition we were enticed by the growing number of
applications.
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