Guest editors' introduction:Special issue on practical development of exact real number computation

Different approaches for real number computations, which deal with arithmetic on the full set of real numbers are presented. Hans-J.Boehm, has shown that how a data structure can be built in a conventional programming language. Valerie Menissier Morain, has shown, how the precision of approximations can be traced during the computation of many basic real functions. Jens Blanck has described methods for computation of iterated maps. Hideki Tsuiki, has described the idea of real numbers computation with logic programming languages. Other important approaches includes geometric computations on algebric numbers, floating point arithmetic with variable precision and fixed precision, and floating point arithmetic enhanced with computer algebra.