It is the purpose of this talk to give a survey on the present status of understanding of the nucleon-nucleon (N-N) interaction. The main emphasis will be put on the theoretical interpretation of the N-N interaction due to its relation to elementary particle physics phenomena at medium energies with the aim to point out that an understanding of the N-N interaction is only possible if one keeps in mind that “mesons are around in the air” if nucleons begin to interact with each other.