introductory vs prefatory

introductory and prefatory both are adjectives.

Word	Noun	Adjective	Verb	Adverb
introductory	No	Yes	No	No
prefatory	No	Yes	No	No

As adjectives, introductory and prefatory are synonyms defined as:

Other synonyms of introductory include prefatorial.

introductory (adjective)	prefatory (adjective)
serving as a base or starting point	serving as an introduction or preface
serving to open or begin
serving as an introduction or preface