The notion of multispace was introduced by F. Smarandache in 1969 under his idea of hybrid mathematics: combining different fields into a unifying field, which is closer to our real life, since we don.t have a homogeneous space, but many heterogeneous ones. Today, this idea is widely accepted by the world of sciences. S-Multispace is a qualitative notion and includes both metric and non-metric spaces. It is believed that the smarandache multispace with its multistructure is the best candidate for 21st century Theory of Everything in any domain. It unifies many knowledge fields. In a general definition, a smarandache multi-space is a finite or infinite (countable or uncountable) union of many spaces that have various structures. The spaces may overlap. A such multispace can be used, for example, in physics for the Unified Field Theory that tries to unite the gravitational, electromagnetic, weak and strong interactions. Other applications: multi-groups, multi-rings, geometric multispace.