The Workshop on Hybrid Formulations of Wave Propagat~on and Scattering underwent a sequence of iterations before emerging in the format recorded here. These iterations were caused by various administrative and logistical problems which need not be detailed. However, its direction being set initially, the iterations led to modifications of the original concept so that the final form was arrived at through an indirect approach. This circumstance may ex­ plain some possible deficiencies which might have been removed, had the final concept been implemented directly. The motivation arose from a perception that the newly restored interest, coupled with new developments, in hybrid methods employ­ ing progressing wave fields and oscillatory wave fields for time­ harmonic and transient guided propagation in manmade or general geo­ physical environments, and for scattering by targets and irregulari­ ties, merits exposure to the wider scientific community. Accord­ ingly, a meeting with highly tutorial content was envisaged. For administrative reasons, related to sponsorship and organizational structure, this objective could not be realized but, eventually, there emerged the possibility of convening an Advanced Research Workshop (ARW) under the auspices of the NATO Advanced Study Insti­ tute Series. The original concept was then modified to accommodate a Workshop, wherein state-of-the-art science is discussed by a relatively small group of specialists, instead of tutorial presenta­ tions of more basic material.