Consisting of 23 refereed contributions, this volume offers a broad and diverse view of late-1990s research in control and estimation of partial differential equations. This volume is primarily geared toward control theorists seeking information on the latest developments in their area of expertise. It may also serve as a stimulating reader to any researcher who wants to gain an impression of activities at the forefront of this expanding area in applied mathematics. Topics addressed included, but are not limited to: control and stability of hyperbolic systems related to elasticity, linear and nonlinear; control and identification of nonlinear parabolic systems; exact and approximate controllability, and observability; Pontryagin's maximum principle and dynamic programming in PDE; and numerics pertinent to optimal and suboptimal control problems.