John Y. Simon was a giant in the field of Civil War-era history whose groundbreaking work on Grant was at the forefront of his generation's reevaluation of Grant's wartime acumen and his controversial presidency, earning him a lifetime achievement award from the Lincoln Forum in 2004 and a Lincoln Prize in 2005. In The Union Forever: Lincoln, Grant, and the Civil War, editor Glenn W. LaFantasie brings together some of Simon's most significant work on two towering figures of their era.

The essays in The Union Forever explore the relationship between the two leaders and their influence on each other as well as their individual accomplishments and struggles. Simon illuminates Lincoln's emancipation policy and his struggles as commander in chief. Other essays explore General Grant's military career and leadership as well as the influence his wife had on his life. Drawing from Simon's most prominent work as well as his lesser-known writing, The Union Forever allows veteran scholars to revisit classic works and makes available to new generations of readers Simon's perspectives on America's greatest leaders during a time of crisis and change.