This study specifically examines three aspects of doctrine concerning the retention and employment of reserves at the tactical level. Should commanders retain a reserve? If retained, should the reserve be kept to the rear, and should the reserve be comprised of only uncommitted forces? The thesis is that doctrine concerning the retention and employment of reserves at the tactical level is not efficient and effective. An evaluation of the historical evolution and application of reserves provide a base from which to understand how doctrine concerning the retention and employment of reserves evolved. These deductions are then applied against the doctrinal application of reserves to determine if they are efficient and effective in today’s tactical environment. Simulation findings are then presented, which further substantiate the doctrinal findings. The historical and theoretical findings indicated that decanting concerning the retention and employment of reserves was efficient and effective. The doctrinal and simulation findings indicated that doctrine concerning the retention and employment of reserves at the tactical level was not efficient and effective. The doctrinal and simulated analysis concluded that a defender can be as, or even more, effective without retaining an uncommitted reserve positioned to the rear of forward troops.