Most notably, it banned "yellow dog" contracts, which allowed employers to forbid employees from joining unions.  
In a way, this piece of legislation overturned the 1896 Supreme Court case Adair v. United States.  Additionally, it was upheld in New Negro Alliance vs. Sanitary Grocery Company.  Also known as the Anti-Injunction Act, it was a key point in the government's sanctioning various methods of striking, as well as barring the government from preventing publicizing labor disputes.  Most notably, it banned "yellow dog" contracts, which allowed employers to forbid employees from joining unions.  FTP, name this 1932 piece of legislation named for Nebraska Senator George and New York City mayor Fiorello.
In a way, this piece of legislation overturned the 1896 Supreme Court case Adair v. United States.  
Norris-LaGuardia Act