  Exerting fluctuations is a part of our daily life: traffic noise, heartbeat,
opinion poll, currency exchange rate, electrical current, chemical reactions -
they all permanently fluctuate. One of the most important questions is why the
systems that exert fluctuations stay long-term stable. Is there any general
functional relation that provides long-term stability despite the wide
diversity of the fluctuations commence: emotions, economics, physical
interactions etc? I assert that such functional relation does exist and reveal
its specification: the route to the long-term stability is through coherence
and boundedness as necessary conditions. It is demonstrated that the chaoticity
is the hallmark of that relationship. The present contribution is a systematic
study written as a book on the relation between long-term stability and
exerting macroscopic fluctuations. Further attention is focused on the
mechanism that guarantees the boundedness and the coherence of the local
fluctuations in the physical systems. Crucial arguments that neither of the
existing so far approaches to the behavior of the extended many-body systems
provides boundedness and coherence of the fluctuations are put forward. It
turns out that the mechanism that brings about macroscopic fluctuations has
universal properties and entangles quantum decoherence, chaos and 1/f noise in
a tricky interplay.
