This issue of Preview features an article written by Ben Witten and Jeffrey Shragge on 'Wave equation imaging and adjoint-state inversion for micro-seismic monitoring'. Ben recently completed his PhD thesis on 3D micro-seismic velocity analysis under the supervision of Professor Shragge. This work, which was supported by the ASEG Research Foundation, has been very well received and has already resulted in the publication of three papers in Geophysics. Ben and Jeffrey's article takes Preview readers right to the cutting edge of this subject.