In the first Lecture we analyze the main types of bosonic and fermionic elementary excitations emerging in thePhysicscondensed matter physics condensed matter physicsCondensed mattercondensed matter physics. They are ranging from phonons in dielectrics and superfluid liquidsSuperfluidsuperfluid liquid and gases, electrons and plasmons in metals till excitons in semiconductorsSemiconductor and magnons in magnetic systemsSystemmagnetic system. We describe different types of the ground stateStateground state in stable and metastable (amorphous) systems.