Interaction is fundamental reality building structure of Universe from quantum physics up to brain neurons interactive actions. Inter-action includes act (act-ual) which causes real. Real inter-action is yes -no actions modeling information Bit. Interactions, creating different chemical, thermodynamic, biological processes, human observations' inter-active actions, cognitive, intellectual, communication, all forms of life, model multilevel interactive bits. Multilevel Information Bits becomes measure of multilevel interactive reality. This book identifies scientific path to fact from of realty through its observed information, connecting Reality, Information and its Observer. The identifying path describes the observing formation of the Observer logic, memory, cognition, encoding Observer intelligence, motor function.The book formalism leads to analytical designed information observer creating AI intellectual brain in the observed discrete reality.