The reader shall find in the offered monograph a systematic presentation of scientific effects in the field of anisotropy studies reached by the author and his collaborators in the period of recent four decades: published and discussed in a number of papers and conference contributions. The central construction line of discussion is to be sought in the full and comprehensive analysis of ret:) function defining the anisotropy coefficient varying during the tensile test. No doubt, this function can be considered as a nutshell carrier ofcomprehensive information about the essential features influencing the directionality of the studied material's plasticity. The function also provides the basis to elaborate methods used in the determination of such characteristics. In the historical presentation of literature in the field of plastic anisotropy, the original input was offered by W.M. Baldwin Jr., already in 1946, who observed the differentiated strain rates in three mutually perpendicular directions of the sample subjected to static tensile test. In the following years, further and expanded analysis of the problem was undertaken by Lankford, Hill, Gensamer, Jackson, Low and Smith.