Don't read the dragon book if you're interested in compilers. It's lex and parse heavy, and is not up to date with more recent best practice on codegen. Further, the lex and parse end of it is focused on the kind of theory you need to build tools like lex and yacc, rather than stuff you need to know if you want to write a compiler.
For a good intro of modern back end development, check out Engineering a Compiler. It's also got the lexical and parsing end of things, but a bit better done, but still quite theoretical.
One of the best books I read on programming is "Concepts, Techniques, and Models of Computer Programming"; it's not strictly speaking language agnostic, based as it is on Oz, but Oz isn't a language you'd ever use in production and is a reasonable base to introduce you to ways of programming that will probably be completely unfamiliar, like constraint programming, dataflow, concurrent logic, etc.
For a good intro of modern back end development, check out Engineering a Compiler. It's also got the lexical and parsing end of things, but a bit better done, but still quite theoretical.
One of the best books I read on programming is "Concepts, Techniques, and Models of Computer Programming"; it's not strictly speaking language agnostic, based as it is on Oz, but Oz isn't a language you'd ever use in production and is a reasonable base to introduce you to ways of programming that will probably be completely unfamiliar, like constraint programming, dataflow, concurrent logic, etc.