Functional analysis plays an important role in the program of studies at the
Swiss Federal Institute of Technology. At present, courses entitled Functional
Analysis I and II are taken during the fifth and sixth semester, respectively. I
have taught these courses several times and after a while typewritten lecture
notes resulted that were distributed to the students. During the academic year
1987/88,1 was fortunate enough to have an eager enthusiastic group of students
that I had already encountered previously in other lecture courses. These
students wanted to learn more in the area and asked me to design a continuation
of the courses. Accordlingly, I proceeded during the academic year, following,
with a series of special lectures, Functional Analysis III and IV, for which I
again distributed typewritten lecture notes. At the end I found that there had
accumulated a mass of textual material, and I asked myself if I should not
publish it in the form of a book.