I recently finished Neil McDonald's "Starting Out: 1.e4!". Now I would like to learn some Black responses. Could someone recommend a book at similar level to Neil's, but focus on Black? 

I'm not sure whether to read several specific books or find one general book (eg with 4 chapters on play against e4, d4, c4, Nf3). One general book to start with would be my preference (so I can pick my favourites), if there is a good one.

By the way, I don't quite like Neil's recommendation on the Scoth game (trade queens, play an endgame where the opponent has a weak pawn). I tried the Scotch gambit a bit. Is there any good resource to go deeper on the Scotch gambit?