How Can I Learn Jazz without a teacher?

I recommend a GOOD chord book..there are several out there to help you finger and spell them out. Know as many positions as you can for each one. Then pick up 'The Johnny Smith Approach To Guitar' by Mel Bay. You can find it on ebay and other web sites. He is a grand master of jazz guitar and one of the greatest teachers / theorists around. Then,,, listen to as many players as you can. Don't try to copy then but learn from their style, phrasing and general feel.

I taught myself how to play jazz from a classical background as a clarinetist years before the Internet existed using my ears and reading skills; in recent years I have added transcribing by merging the ears and reading skills (admittedly helped by the advent of computer notation and digital audio media; repeating an idea or phrase is so much easier than in the days of tape and LP's!). While I have not ever had a formal teacher in my jazz studies, I have had mentors: some were players, some were avid long-term jazz fans who were also journalists, but all somehow contributed in shaping my explorations as a musician. A mentor might show you matters of technique or theory, but the mentor really is there to "put a compass on the ship" (as said the principal of teachers in "Mr. Holland's Opus"; yet of all the teachers I've encountered only a handful truly challenge minds as mentors do). One was a sax player with whom I never discussed technique, but about how to learn tunes and musical standards; another, a bassist who showed me a bunch of cool voicing tricks. Yet another was a photographer who reminded me that "the holes in my Swiss cheese could well be another's Swiss cheese"- that still resonates as a challenge to absorb from any and all sources that my horn can do. My mentor of nearly twenty years does talk technique with me sometimes, but mostly as it applies to execution of an idea rather than pure mechanics. When I met him at a jam session I was so knocked out by his ideas and execution that I asked him if I could study from him. He demurred, saying that I had something that no one taught at music school (he had done his junior year at North Texas State)- a working pair of ears. He encouraged me to hang out with him as much as possible to absorb not just content but context. Go hear as many local artists as you can in the search of such figures; sometimes they just might be in the audience listening to the gig just like you. As Charlie Parker remarked, "If you haven't lived it- it ain't in your horn!" So listen, listen, listen- whether you're practicing or not, and seek out those who do also for feedback. Don't just listen to guitarists: listen to horn players (the early guitar solos supplanted the sax solos on '50's R&B records), pianists, and especially tasteful vocalists for phrasing (can't go wrong with Ella Fitzgerald, Frank Sinatra, Mel Torme, or Sarah Vaughan for starters). As for books on guitar technique I am as a wind player unqualified to answer, but the Jazz Theory Book by Mark Levine which Robin D mentioned is a great choice for theory comprehension as applied to jazz harmonies. Best wishes for your development as a jazz guitarist.

If you play guitar, (western classical) then you know the notes on the neck of a guitar. My advice is to learn as I learned, and how thousands of others including paid professionals have learned, listen to your favorite artists very closely and carefully and play along. The more you do it, the better you become. The more you listen to your favorite artist, you'll soon realize that that particular artist uses a lot of he same notes, in the same pattern, at the same tempo, in the same key. It's the comfort hook that was catchy and got them where they are now, getting paid doing what they do. So listen and play along, you'll get it.