Mark Evanier has a great page that gives background and art on the comic in question and other Marvel covers that were rejected for one reason or another.

http://www.povonline.com/Alternatecovers.htm

I can't help it.

Thanks for the link. I think I understand more why he left Marvel, he wanted more freedom to do what he wanted to do, and I this seems to be what JB referred to in the FF thread when I asked about FF:

http://www.povonline.com/jackfaq/JackFaq2.htm

Added: This is probably a piece of history that you know, but I have only heard the Stan Lee version.

Greg Theakson's "Pure Images" issue on the creation of Spider-Man gives the series of events as Joe Simon and C.C. Beck creating a Captain Marvel-like character in the "Silver Spider." A young orphan living in a home with a cruel elderly couple is locked in the attic where he finds a magic ring that allows him to summon a comical, bowler-derbied Genie who grants him super powers and an adult form.  Whatever publishing arrangement Simon had to print this comic fell through.  Later, he and Kirby created the Fly, another insect based hero, built almost entirely upon the foundation of the Silver Spider concept.  Tommy Troy, an orphan living with a cruel elderly couple is locked in the attic where he finds a magic ring that summons Turan, an emissary from another dimension, who grants him super powers and an adult form. The Fly carries a "buzz-gun." Later writers on the strip dispensed with the child-to-adult idea and simply gave the Fly's alternate identity as Thomas Troy, attorney.  Kirby went from there to several other publishing ventures.  For one of these, he developed a character called "Night Glider" (not the later Topps character) who used gimmicks and paraphenalia to scale walls. This character carried a gimmick gun and wore goggles that enables him to see in the dark. The article says that when Lee was casting about for super-heroic concepts to continue the success of the FF (also a strip bearing very heavy resemblance to Kirby's earlier work), Kirby developed a version of Spider-Man incorporating various elements of his earlier characters.  A young orphan living in a home with an elderly couple who develops insect powers and creates gimmicks and paraphenalia, such as a web-gun, to create an adult-looking identity for himself.  These pages are the ones Lee rejected, turning the project over to Ditko.

Ditko composed a response to the creator controversy (I wish that I could recall where it was published) in which he attributes the origin of the Spider-Man idea to Lee who gave the script to Kirby first. Kirby turned in pages with a typical muscleman physique and a web-gun.  Lee then turned the project over to Ditko, who claims sole credit for Spider-Man's eerie and innovative costume and visuals. Who then is the creator, he asks? The writer, who merely puts the vague concept to paper? The first artist, whose work never saw publication? Or the later collaborator who created the look of the hero for a visually dynamic medium, and went on to shape the series and plot many of that hero's most memorable and definitive adventures? He gives this illustration for what he recalls of Kirby's design for the character:

Jack Kirby was often ahead of his time. The link Lar provided to Mark Evanier's website had this interesting tidbit:

Mark Evanier wrote: ...When Jack went to DC, one of the things that most interested him was the prospect of doing new forms of comics — graphic novels, upscale magazines, etc.  He had little interest in and did not see much of a future for the conventional 32-page comic.  Ergo, he hoped to launch the Fourth World books and pass them on to others who would do them under his editorial supervision, while he worked on new forms....

I made some mention in past threads of what I think needs to be done to save comics, including changing the format:

http://www.byrnerobotics.com/forum/forum_posts.asp?TID=13413 &KW=future

http://www.byrnerobotics.com/forum/forum_posts.asp?TID=14816 &KW=future

It seems that Jack Kirby thought along the same lines back in the early 1970's.

About the overall subject at hand, with this thread:

I look at Stan Lee, Jack Kirby, and Steve Ditko as being the comic book counterparts to the Beatles, primarily John, Paul, and George.

All contributed something of great value in their partnership, and while people, even the creative people involved themsleves, might argue who contributed how much and what, I don't think any knowledgable and sensible person could argue that just as the Beatles wouldn't be "The Beatles" without all the members I named, neither would Marvel had been "Marvel" without Stan, Jack, and Steve.

ALL three men were essential ingredients to what made Marvel.

Brian wrote: ...Greg Theakson's "Pure Images" issue on the creation of Spider-Man gives the series of events as Joe Simon and C.C. Beck creating a Captain Marvel-like character in the "Silver Spider"...

Joe Simon's own autobiography gives the same  story about the creation of Simon & Jack's "Spider-Man," which became the "Silver Spider," which became "The Fly."

Steve Ditko created Spider-Man, and never made a nickel more than his page rate for doing so. Can we please stop these insane efforts to strip the man of the credit he is due? Can we please go forth and beat the living crap out of the next moron who says Kirby created Spider-Man?

Stan saw a fly and created Spider-Man

Jack started with a spider and created the Fly?

weird wild stuff.

Michael wrote: ...I can't see that version of Spider-Man being as successful....

Jack Kirby had many wonderful, successful ideas, but that was just a rehash of The Fly, which borrowed heavily from Captain Marvel, as others have noted.

The creation that Stan Lee and Steve Ditko came up with (I believe that Jack didn't have anything to do the creation of the Spider-Man we all know and love) was so unique, both in character and appearance.