It's hard to imagine a better literary example of the perfect single father than Atticus Finch in the novel To Kill a Mockingbird. Atticus is left to bring up his children alone after his young wife died of a sudden heart attack. Although Atticus is much older than most of Jem and Scout's friends, it is his wisdom that helps to guide his children through life in tiny Maycomb. He always finds time each day to read with Scout, and when the kids need to have a heart-to-heart talk, he makes himself available.
He gives the children more independence than most parents, and they respond by trying to make him proud of them. When Jem makes the seemingly reckless decision to return to the Radley House to retrieve his lost pants, he tells Scout
"Atticus ain't ever whipped me since I can remember. I wanta keep it that way."
Jem does not fear a whipping (Atticus apparently has never spanked either of them); he just doesn't want to disappoint Atticus. He allows them to watch the remainder of the rape trial (after sneaking in and being discovered) despite the ire of Alexandra and Calpurnia.
Atticus always speaks the truth with Jem and Scout, telling his brother, Jack,
"When a child asks you something, answer him, for goodness' sake... they can spot an evasion quicker than adults."
He allows them the freedom to curse once in a while, but he cautions them about using the word "nigger." It's "common," he tells Scout. He debates his sister, Alexandra, about the wisdom of making Scout more lady-like, allowing her to wear her beloved overalls constantly. In the end, the children turn out okay. We know this from the first pages of the novel, when the grown-up Scout seeks out a much older Atticus for advice--just as she had when they were children. The diplomatic but straight-shooting Atticus "said we were both right."