I had a collection of hundreds of guitar books at one point I think, though that was a while ago. I've made another comment here - the Berklee modern method boo

I had a collection of hundreds of guitar books at one point I think, though that was a while ago. I've made another comment here - the Berklee modern method books are great for guitar. Also, learn a ton of songs if you can. There's no better way to work on technique than learning songs. I can suggest specific books if you mention what style of guitar you're learning to play...