"Si Klegg: Book 4" is the fourth installment in the Si Klegg series by John McElroy. The series follows the fictional character Si Klegg, a young Union soldier who enlists in the army during the American Civil War. In this book, Si and his fellow soldiers continue to experience the trials and tribulations of army life, including battles, injuries, and illnesses. They also face challenges with their superiors and fellow soldiers. Along the way, Si grows and matures, gaining valuable experience and insight. Si and his comrades develop strong bonds as they endure the hardships of war together. The book also explores the effects of war on individuals and society, as well as the complexities of leadership and authority.