The Party Organizer was the organizational publication of the Communist Party USA (CPUSA), complementing its ideological magazine Political Affairs. Prior to 1978, the Party Organizer was known as Party Affairs.
In the words of the Party Organizer itself,
In the new conditions, when there are many questions of how to organize successfully, the Party Organizer provides a format for reporting experiences, probing them, sharing the lessons they have to offer and finding the outstanding examples that serve as models enabling the entire Party to generalize the successes achieved in particular clubs or districts. Specific breakthroughs can become an overall general breakthrough. Specific mistakes can be limited to those who first make them and learn from them.
Party Organizer, Volume 12, No. 1, January 1978.
The Party Organizer, Political Affairs, and Party Affairs are all available on the American Archive of Marxism-Leninism, a project of the Party of Communists USA:
Party Organizer: https://leninists.org/index.php/Party_Organizer
Party Affairs: https://leninists.org/index.php/Party_Affairs
Political Affairs: https://leninists.org/index.php/Political_Affairs