Superconductivity and superfluidity have already been studied for almost one century. In the case of superconductivity one may say it reached its peak with the dramatic appearance of BCS (Bardeen–Cooper–Schrieffer) theory in 1956. Since it was so successful, the research developed at an explosive rate, and by the beginning of the 1970s we thought the fundamental theories were well established. It is therefore logical that many of the well-known texts on superconductivity were written during this period. Superfluidity of liquid 3He was also studied most actively during the early 1970s. Many people therefore had the impression that research in the field of superconductivity and superfluidity had already reached its peak. However, much interesting progress has been made since then. First, the superfluidity of liquid 3He due to non-s-wave pairing was discovered in 1973, and became the subject of intense research, both experimental and theoretical. The generalised BCS theory again turned out to be quite successful, and over about ten years we obtained a basic understanding of this phenomenon. In the 1980s, stimulated by the superfluidity of liquid 4He, people started to look for non-s-wave superconductivity in the heavy fermion systems. Then, rather unexpectedly, we witnessed the biggest event of recent years, namely the discovery of copper oxide high temperature superconductors by J.G. Bednorz and K.A. Müller in 1986 ([G-1]).

With this rich history before us, it is clearly an extremely difficult task to decide which topics to cover.