Cassius was a truly exceptional police dog whose career became the stuff of legend and the gold standard for all dogs coming after. In just five years he scored a century of arrests, saved lives, bit half a dozen policemen, and gave his handler, PC Joe Sleightholm, the most exciting, exhilarating, and nerve-wracking times of his life. Things did not go according to plan in Sleightholm's first years as a police dog handler. The difficulties of finding...