Here are some notes and solutions to accompany Anthony Zee's textbook Quantum Field Theory in a Nutshell, 2nd edition (Princeton University Press, 2010). As always, I give no guarantee that the solutions are all correct, so if you spot any errors, please do leave a comment.
I’m not aware of any online list of errata for this book. (There is an errata page for the first edition, but presumably these errors have been corrected in the second edition.) If anyone knows of an official errata site for this book, please leave a comment below.
Part I: Motivation and Foundation
Chapter I.2: Path Integral Formulation
Delta function, Gaussian integrals, Gaussian integrals: averages, Steepest descent