The lecture notes are available from the Syllabus web page.
You will need an Adobe Acrobat Reader or an alternative pdf viewer
to view or print some of these files,
the ones with .pdf extensions.
If you don't have one, Adobe Acrobat Reader is available for free:
Where I have typed lecture notes out (which is
mostly be when they differ sufficiently from Peskin), they are posted
on the Syllabus web page.
Latexed Lectures are available in full format for easier on screen reading,
and reduced to two pages/side for more efficient printing. Click on
"view" or "print" respectively.
There are also a number of supplemental notes, which are available
from the Supplementary Notes web page.