How many editions of the 'Superman' comic book have there been?

Answer 1

2.

Superman (1939) - 1 - 423
Changes to Adventures of Superman in 1987 from 424 - 649
and then in 2006 returns to its original numbering at issue 650 under the title Superman.

In between there was another Superman book that ran from 1987 until 2006 for 226 issues.

There are also other books that feature Superman:
Current:
Action Comics
Superman/Batman
Superman Confidential
All Star Superman

Previously:
Superman: The Man of Steel
Superman: The Man of Tomorrow

Also, at times Action Comics was called Superman in Action Comics.

There were also books in the Silver age such as:
Superman's Girl Friend Lois Lane
Superman's Pal Jimmy Olsen
Superman Family

And there has been other books Superman has been in:
Justice League or JLA or Justice League of America
Many of the Crossover books (Infinite Crisis, Identity Crisis, Our Worlds at War, etc.)