This paper is a brief survey of the m-M calculus. The m-M calculus deals with the so-called m-M functions, i.e. functions of the form f:D→R(D=[a1,b1]×…×[an,bn], where n>0 is any integer and ai,bi ∈ R) subject to the following supposition: For each n-dimensional segment Δ = [α1,β1]×…×[αn,βn]⊂D a pair of real numbers, denoted by m(f)(Δ), M(f)(Δ), satisfying the conditions m(f)(Δ)≤f(X)≤M(f)(Δ) (for all Δ⊂D, X∈Δ) and lim(M(f)(Δ)−m(f)(Δ))=0 (where diamΔ:(Σ(βi−αi)2)1/2) is effectively given. Such an ordered pair 〈m(f),M(f)〉 of mappings m(f),M(f) (both mapping the set of all Δ⊂D into R) is called an m-M pair of the function f. We also say that m(f),M(f) are generalized minimum and maximum for f respectively. For instance, with only few exceptions all elementary functions are m-M functions (Lemma 1.2).