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The use of the crack tip stress intensity factor, K, has survived almost 50years as the key parameter correlating fatigue crack growth. As time past the range ofthe stress intensity, ΔK , was recognized as causing alternating plasticity at the cracktip. The threshold level for ΔK was discovered. Further the occurrence of crack closurewas noted which effected the ΔK for different load ratios, R, of cyclic loading. TheASTM method of counting the linear part of the load displacement for determiningΔKopen was found to understate the ΔKeffective, which correlates data for differentload ratios. One approach to adjust for this problem is the “Partial Closure Model”,where the closure only occurs away from the crack tip. Here it will be discussed thatsuch a model leads to a universal growth law. Moreover, this law shows application inestimating the order of magnitude of crack growth life (>107cycles) for example withvery high cycle fatigue (>109cycles). Some advances in this application will also becited.