What's the difference? Can strength be gained without increasing bulk? Can strength be increased without increasing muscle mass? Biochemically speaking, how do the processes differ if at all?
E.g. can I get stronger without getting heavier? (and without losing fat)
If I get stronger will my muscles necessarily become larger?
Is there any neurological aspect to strength training?
I realize this question is a bit vague, but I lack the knowledge to ask suitably specific questions. So please feel free to tell me I need to read up on X, Y and Z.