* Different printings: There have been countless printings of the book over the years, with slight variations in cover art, binding, and even minor editorial changes.
* Different formats: "Of Mice and Men" has been published in various formats, including paperback, hardcover, audio books, e-books, etc.
* Special Editions: There are also special editions for schools, collectors, and other purposes, with unique features.
Therefore, it's impossible to say how many "editions" there are in a definitive sense. It would be much more accurate to say that "Of Mice and Men" has been published in countless different formats and editions since its initial release in 1937.