2 Resources share the relationship http://bibfra.me/vocab/relation/local/writerofforeword to Schwarzenegger, Arnold

Tools of titans, the tactics, routines, and habits of billionaires, icons, and world-class performers, Tim Ferriss ; foreword by Arnold Schwarzenegger ; illustrations by Remie Geoffroi
You can't screw this up, why eating takeout, enjoying dessert, and taking the stress out of dieting leads to weight loss that lasts, Adam Bornstein ; [foreword by Arnold Schwarzenegger]