  This article reviews recent years' progress in the low temperature analysis
of standard models of spin glass order such as the Sherrington-Kirkpatrick (SK)
model. Applications to CdTe/CdMnTe layered systems and explanation of glassy
antiferromagnetic order at lowest temperatures stimulated us to study in detail
the beautifully complex physical effects of replica symmetry breaking (RSB).We
discuss analytical ideas based on highly precise numerical data which lead to
the construction of relatively simple effective field theories for the SK model
and help to understand the mysterious features of its exact solution. The goal
is to find construction principles for the theory of interplay between
frustrated magnetic order and various relevant physical degrees of freedom. The
emphasis in this article is on the role of Parisi's RSB, which surprisingly
creates critical phenomena in the low temperature limit despite the absence of
a standard phase transition.
