Predictability isn’t a word you will find in any Bushveld dictionary, and the life of wildlife guardian Mario Cesare has been anything but. After years as warden of Olifants River Game Reserve, his feet are firmly planted in this magnificent slice of Big Five country to the west of the Kruger Park, where he has experienced a rich life packed full of incidents far from routine.

In Heart of a Game Ranger, Cesare recounts some of these hair-raising, heart-breaking and heart-warming moments: a buffalo calf reunited with its pining mother, injured lions given second...