Greatest Songwriter of all time

maybe not the greatest but deserves to be mentioned- Paul Simon

No mention of David Bowie? He has been one of the biggest influences on rock/pop of the last 30 yrs. And XTC, the greatest underrated act of recent memory.

BUT, nothing has ever touched my soul like a Mozart aria. God sang into this man's ear as he wrote down the notes.

This is an impossible question!
Who is the most beautiful woman ever?
' depends what day you ask me.
But I will put forth a few names that I believe that by any objective evaluation can not be denied. One of the primary factors I consider essential to be on my list is the songwriters influence on other songwriters and their continuing influence on newer, younger generations of songwriters.

The Gershwin brothers - A great organic blend of lyric and music.
Hank Williams - Heart on his sleeve. Great songs to cry in your beer to. Heartache incarnate.
Bob Dylan - The Picasso of songwriters. How many "periods" has he gone through? Songs about everything in the human experience...and beyond.
Bob Marley - Voice of the voiceless.
Puccini - Soars and pulls the heart strings. Beautiful drama.
Cole Porter - Elegant, smart
Antonio Carlos Jobin - Smooth, sexy, beautiful
Marvin Gaye - What's Going On - An inner-city symphony of 1971 America. Young man back from the war. Strung-out. People,the earth abused.
The songwriter of the love song you hear on your car radio Saturday night when your crusing with your girl by your side. And that song is saying everything that is inside you.

Smokey Robinson
Becker and Fagan
Jesse Winchester
Tom Paxton
Donovan
John Prine
Gil Scott Heron
McGarrigle Sisters
Stan Rogers

Some others for your consideration.

king David
and Leonard Cohen, and Bialik