When systems thinker Barry Oshry felt dismissed and disregarded by an organization that had meant so much to him, rather than simmer and sulk, he struck back with a remarkable weapon. He wrote a letter. It was a most unusual letter, a letter to a system in whole and in parts. It was addressed to specific individuals, to leaders and members, past and present, and, in its way, it was addressed to all of us who have ever suffered indignities at the hands of our organizations. In this anniversary edition, with a new introduction and additional information and analyses, Oshry continues to illuminate system life for all of us. The Systems Letter offers valuable insights for both the oppressors and the oppressed, and offers hope and inspiration to all those who feel diminished, dismissed, and disrespected by their organizations. "A warning about the Systems Letter: Once you start, you will not be able to put it down. You will be reading the work of an organizational anarchist who understands systems better than anyone… Oshry's Letter is written to you and to me making it all the more personal and meaningful. And one final warning: On completion of your reading, to borrow a phrase from the Systems Letter, 'the last traces of your innocence (regarding systems) will be gone'". W. Warner Burke Edward Lee Thorndike Professor of Psychology and Education Teachers College, Columbia University