We are pleased to announce that the 3rd ICFA Mini-Workshop on Deflecting/Crabbing RF Cavity Research and application in Accelerators will be held in July 18-20,2012, at the Institute of Modern Physics (IMP), Lanzhou, China. This workshop is hosted by Tsinghua University (THU), Beijing, China, and sponsored by Tsinghua University, Lawrence Berkeley National Laboratory (LBNL) and Argonne National Laboratory (ANL). Deflecting/Crabbing RF cavities have been proposed, designed and built for increasing luminosity by creating "head-on" collisions in high energy colliders, generating short x-ray pulses in synchrotron light sources, bunch separation and combination, emittance exchange techniques and as a beam diagnostic. Much progress has been made in deflecting/crabbing cavity R&D. The purpose of this workshop is to bring together researchers in various accelerator communities and discuss advances in deflecting/crabbing RF cavity R&D. Topics of interest: High energy colliders (ILC, LHC, KEK-B, CLIC, ...); Generation of short x-ray pulse in synchrotron light sources; Beam manipulations, emittance exchanges and diagnostics; Deflecting cavity design optimization; Novel deflecting cavity design.