What role does Meyer Wolfshiem play The Great Gatsby?

The character Meyer Wolfshiem in The Great
Gatsby allows Fitzgerald to satirize the American Dream and the Roaring
Twenties.  Wolfshiem is also used to reveal details of Gatsby's
business.

Wolfshiem is a Jewish gangster (some think this
reveals anti-semitism on Fitzgerald's part) who fixed the 1919 World Series (in
the world of the novel).  He also, presumably, is a bootlegger.  He lives "under the
radar," as they say, trying to not draw attention to himself so that the police do not
pay too much attention to him.  This, suggests the novel, is how
one gets rich in America and fulfills the American
Dream. 

Wolfshiem as a character also helps the author
reveal the shallow nature of the people in the American twenties.  He claims to be such
a good friend to Gatsby, yet he won't even attend his funeral.  He is self-centered and
superficial and hypocritical.   

Wolfshiem, together with
people like Daisy and Tom and Jordan, is what the American Dream is all about in
The Great Gatsby.

Gatsby's connection
with Wolfshiem also reveals a bit about Gatsby's business.  While Gatsby's occupation
still remains somewhat of a mystery, the romance is certainly taken out of the issue. 
His work puts him in the league with Wolfshiem, and that's not a good
league.