This volume contains the results of the workshop on Parameter Identification and Inverse Problems in Hydrology, Geology and Ecology , held in Karlsruhe, Germany, and represents a selection of contributions from the various groups of participants. The reviewed, invited and contributed articles are grouped according to the broad headings of hydrology, non-linear diffusion and soil physics, geophysical methods, mathematical analysis of inverse and ill-posed problems and parallel algorithms for inverse problems. The book also contains the three-lecture tutorial Introduction to Inverse Problems of Non-linear Partial Differential Equations for Physicists, Scientists and Engineers by Paul DuChateau, held at the Workshop.