I apologize if this has been posted a million times. I'm looking for good instructional books that cover the basics but could essentially be applied to intermediate levels of playing. I am able to play several songs (typically those with a handful of chords) but have never mastered much beyond that (except for bron-yr-aur, which I'm very proud of). I play both acoustic and electric and I'm looking for books that can explain as much of the basics as possible but also allow me to move beyond playing songs based solely on chords. I'm looking to begin utilizing scales and arpeggios as well as multiple strumming / finger-picking styles, and anything else I can learn.

Basically looking for the "essential" instruction manuals. Thanks for your help!
Books may work for some but I find visual and verbal instruction to be much better. Have you looked into on-line lessons? Many available and many are free. justinguitar and guitarjamz are good places to start and there are many more. A chord dictionary is also helpful.
Thanks! I'll definitely utilize those resources. Guess I have always learned best through reading but I can see why visual instruction is can be helpful when it comes to guitar instruction.