The term 'stereotype space' was introduced in 1995 and is used for a category of locally convex spaces with surprisingly elegant properties. In particular, it consists of spaces reflexive in the sense of Pontryagin, and at the same time it is very wide, since it contains all Fréchet spaces. Its study gives an unexpected point of view on functional analysis that brings this field closer to other main branches of mathematics, namely, to algebra and geometry.