Mike Leach’s trailer was putrid.

It was 1989, and Leach was making $12,000 a year to coach the offense of Iowa Wesleyan’s football team. The nicest thing about his trailer home was the waist-high grass outside. Inside was a broken shower, a constantly overflowing toilet and a low-hanging ceiling fan that nearly decapitated Leach and his wife. The walls, floor and ceiling were covered in a bright red shag rug. The suffocating dust and mildew invigorated his asthma.

That...