ABSTRACT
In this chapter we will describe in more detail the developments summarized in §1.6.
We have already referred in §5.3.3.5 to a paper by Essam and Fisher (1963) on Fade approximant studies of critical exponents for temperatures below Tc. In the final section of this paper they raised the question of possible relations which might exist between critical exponents, and introduced 'with due caution' a heuristic model which they hoped might have 'some suggestive value' in relation to critical behaviour. The model was elaborated by Fisher in a lecture given at the Centennial Conference on Phase Transitions held at the University of Kentucky in 1965, and published in 1967.
