Abstract
A review of the methods applied for the investigation of long-range stresses in deformed single crystals is given. The results found by magnetic methods are discussed in some detail; slip-line data and transmission microscopy are mentioned briefly. The effect of internal stresses on the flow stress is discussed and it is shown that the elastic interaction between the primary dislocations determines the flow stress almost completely. Secondary dislocations are found to be incapable of relaxing the stress fields of the primary dislocations appreciably.