拙著 is a self-deprecating courtesy term, only use about your OWN writing, never someone else's. Part of the
拙- family of humble self-references:
拙作 (my humble work),
拙见 (my humble opinion),
拙荆 (my wife, very old-school). For a respectful reference to someone else's book, use
大作 or
尊著.
