If you already know how to program, ie you know what it means for something to be of a "regular" or "context free" grammar, you have coded a B+ tree and hash buckets in a functional language, and know what polymorphism is, then I'd suggest skipping straight to Programming Perl. It covers everything that Learning Perl does IMO, and in a style well suited to people who don't need their hand held whilst introducing some of those concepts.