Substitution-Failure-Is-Not-An-Error (SFINAE) is decribed in CppTemplatesTheCompleteGuide p.106 and also in CppCommonKnowledge Item 59 p.217.

''This [...] principle is clearly an important ingredient to make the overloading of function templates practical.''

There is also a page on this on WikiPedia:
*** http://en.wikipedia.org/wiki/Substitution_failure_is_not_an_error

One of the CeePlusPlusIdioms
----
This page may not reflect changes in C++11(CeePlusPlusEleven) and C++14(CeePlusPlusOneWhy).
----
CategoryCpp CategoryCppTemplates CategoryIdiom