For most people at my school one's hardest shelf of 3rd year is either medicine or surgery, whichever one of the two that you have first. I had medicine first so it was by far my worst score and the one I came least closest to actually finishing (I only finished 1 shelf all year). Do not freak out if you don't finish, it does not mean you will fail, I still did above the mean on all of mine. Do not expect to ace your first shelf, this is a totally new testing format for most of us and it takes getting used to. Most people improve considerably as the year goes on. As for surgery specifically, Lawrence is a great book if you have the time (I didn't, I think I read like 3 chapters), FA is okay (but I don't like FA in general), I thought case files was pretty good and Kaplan notes are ok (although not quite the magic bullet I had been led to believe). Personally I think Pretest is a waste of time for surgery, those questions are way too esoteric in many cases and too specific to actual surgeries, which there will none of on the actual exam. They will not ask you about what type of incision, how to drain an abscess, what suture material to use, details of how to do a lap chole, etc. They will ask you what might be the cause of a pt's temp of 102 on POD #1 s/p a lap chole. Focus on diagnosis and post-op management. Hope this helps.