  The R-matrix formalism for the construction of integrable systems with
infinitely many degrees of freedom is reviewed. Its application to Poisson,
noncommutative and loop algebras as well as central extension procedure are
presented. The theory is developed for (1+1)-dimensional case where the space
variable belongs either to R or to various discrete sets. Then, the extension
onto (2+1)-dimensional case is made, when the second space variable belongs to
R. The formalism presented contains many proofs and important details to make
it self-contained and complete. The general theory is applied to several
infinite dimensional Lie algebras in order to construct both dispersionless and
dispersive (soliton) integrable field systems.
