Project Rebirth was a secret US government project administered by the US Army to create Super Soldiers for its World War II efforts. Steve Rogers joins the program that turns him into Captain America.
Steve Rogers was chosen by Abraham Erskine to become a Super Soldier with the Super Soldier Serum. The test was successful (unlike Project Master Man), but Heinz Kruger shot Erskine and took the serum. After Erskine's death, Rogers killed Kruger, avenging the good scientist's death.
After that, the serum was lost, and the project was disbanded.