I could say she is an enormous talent, but that would be a huge understatement.  I just finished "Reckless Daughter:  A Portrait Of Joni Mitchell" by David Yaffe.  Easily one of the greatest rock bios I've ever come across.  Yaffe is quite a writer and has appeared in many publications including The New York Times and The Village Voice.  He is the author of "Bob Dylan:  Like A Complete Unknown".  He really understands Joni's music and her unique and brilliant guitar tunings.  Maybe most amazing is that Joni learned to play guitar from a Peter Seeger instructional manual.  Yaffe is very honest about Joni the person.  Complex would be the easiest way to describe her, and former friends and lovers are allowed to express opinions of Joni the person, even if they don't happen to be very complimentary.  Huge Joni fans include Prince, Jimmy Page and Robert Plant, who was so nervous that he avoided talking to her at a party.  The line in Going To California, "she plays guitar and cries and sings" is actually a tribute to Joni!  Here's another tidbit from the book:  Jackson Browne comes off as a bit of an oddball, and not real kind in his treatment of women.