Symposium on Non Well Posed Problems and Logarithmic Convexity : Held in Heriot Watt University Edinburgh Scotland March 22–24 1972 Some general remarks on improperly posed problems for partial differential equations Logarithmic convexity and other techniques applied to problems in continuum mechanics Cauchys problem and the analytic continuation of solutions to elliptic equations Some properties of solutions of the Navier Stokes equations Non unique continuation for certain Odes in Hilbert space and for uniformly parabolic and elliptic equations in self adjoint divergence form Logarithmic convexity and the Cauchy problem for P(t)utt+M(t)ut+N(t)u=C in Hilbert space Stabilized quasi reversibilite and other nearly best possible methods for non well posed problems.