The preceding observations give an indication of the problems involved in preparing the German field forces for an encounter with an opponent whose pattern of behavior and thinking was so fundamentally different from their own that it was often beyond comprehension. Moreover, the peculiarities of the Russian theater were such that German unit commanders were faced with situations for which there seemed to be no solution. The unorthodox Russian tactics with which the Germans were not familiar were equally disturbing, and Russian deception and trickery caused many German casualties. Several months of acclimatization were often necessary before a unit transferred to Russia was equal to the demands of the new theater. Occasionally a combat efficient unit without previous experience in Russia failed completely or suffered heavy losses in accomplishing a difficult mission that presented no problems to another unit familiar with the Russian theater, even though the latter had been depleted by previous engagements. This fact alone proved how necessary it was to disseminate the lessons learned in Russia, since this was the only method by which inexperienced troops could be spared the reverses and heavy casualties they would otherwise suffer during their commitment against Russian troops. To meet this need for training literature, a series of pamphlets and instructions based on German combat experiences in Russia was issued in 1943-44.