Judge Thatcher is Becky's dad, and, as his name suggests, he's a judge. Judge Thatcher is the closest thing Tom has to a role model; he's a fine father and a good citizen. He searches tirelessly for Becky and Tom when they get lost in the cave and takes the utmost care in making sure that no one ever gets lost again by sealing the cave off with a big old metal door. His judgment is, perhaps, not entirely sound. At the end of the book, he comes to believe that Tom will end up being a great soldier or a lawyer.