Hey Virgil: You may have noticed,
RSC is the lead reference I use for Roman silver. I have the entire set including
Vol. I. As the title implies,
RSC I includes what many of us call
imperatorial issues. I think it is a great reference alone, but supplement with
Sydenham and
Sear HCRI where appropriate. (I too would like to have
Crawford but will await the next reprint hopefully in affordable paperpack.) If you have or have seen any of Volumes II through V,
Vol. I is similar with respect to the technical descriptions of the coins, representative (but not comprhensive) plates, and some discussion of historical characters and events. I certainly think it's worth the modest cost.