Isaac Summerfield I was the Summerfield that Christine Summerfield felt the most sympathy for. She got the impression that he was a "nervous, paranoid, and messed up person".
He was born in 2365 as the child of a two year old toddler created as part of an experiment in super-fertility. He spent most of his life "being shunted from one space-age housing project to another".
In 2389, Isaac and his lover had a child. In an attempt to bring back his family's "glorious military past", Isaac named the child Marshal Summerfield VI. Before the year ended, Isaac gave his son to the Earth military.