We address the problem of time-domain inverse scattering, where we want to determine some unknown characteristics of an object from measurements of the reected field. The IMPACT inverse method is described first in a general case in section 1 and then applied to three different solvers for vibro-acoustics, pure acoustics and electromagnetics in sections 2-4. In section 5 the optimisation problem and the structure of the code is discussed. Relating to the workplan, section 1 corresponds to task 1.5, sections 2-4 to the tasks 1.2 and 1.3 and section 5 to task 1.4. The description of the direct codes are
kept in appendices A-C. The contents of section 1-5 are summarised.