These notes grew from an introduction to probability theory taught during
the first and second term of 1994 at Caltech. There was a mixed audience of
undergraduates and graduate students in the first half of the course which
covered Chapters 2 and 3, and mostly graduate students in the second part
which covered Chapter 4 and two sections of Chapter 5.
Having been online for many years on my personal web sites, the text got
reviewed, corrected and indexed in the summer of 2006. It obtained some
enhancements which benefited from some other teaching notes and research,
I wrote while teaching probability theory at the University of Arizona in
Tucson or when incorporating probability in calculus courses at Caltech
and Harvard University.
Most of Chapter 2 is standard material and subject of virtually any course
on probability theory. Also Chapters 3 and 4 is well covered by the literature
but not in this combination.