Finally, to add value to the revised edition of my book, I tried crunching numbers and doing a statistical analysis of the fighting. This also drew on my previous readings in military history over the years. Reasonably reliable figures were available for numbers and losses on the Union side. Figuring out Confederate numbers and losses ordinarily requires more work. Once I had the numbers, I drew generally upon the work of Beninger, Hattaway, Jones and Still in Why The South Lost The Civil War and Dupuy in The Evolution of Weapons and Warfare. The model I employed came from Dupuy's A Genius for War: The German Army and General Staff, 1807-1945. The results put Grant's modest achievement in his Fourth Offensive at Petersburg in a very positive light. To have made any progress against the Confederates with his relatively inferior troops despite his three to two numerical superiority testifies to Grant's talent and skill as a commander.