📕 The fourth book in the Olivier & Joaquin series, Navigating the River of Time, sees the two brothers travel back in time, where ancestors help them through the pivotal 1746 Battle of Rocourt in Europe, Mexico's Cinco de Mayo and Battle of Puebla in 1862, and the final days of World War II, before working the family farm in the Midwest of North America immediately after that war and helping their grandmother build a school in Asia.