The second edition of this book differs from the original in three respects. First,
we have eliminated a large number of typographical errors. Second, we have
corrected a small number of mathematical oversights. Third, we have rewritten
several subsections in order to incorporate new or improved results. The principal
changes occur in Chapters 3 and 4.
In Chapter 3, Section 3.1.2 now contains a more comprehensive discussion
of dissipative operators and analytic elements. Additions and changes have also
been made in Sections 3.1.3, 3.1.4, and 3.1.5. Further improvements occur in
Section 3.2.4. In Chapter 4 the only substantial changes are to Sections 4.2.1 and
4.2.2. At the time of writing the first edition it was an open question whether
maximal orthogonal probability measures on the state space of a C*-algebra
were automatically maximal among all the probability measures on the space.
This question was resolved positively in 1979 and the rewritten sections now
incorporate the result.