Prefatory

(a.) Pertaining to a preface; introductory to a book, essay, or discourse; as, prefatory remarks.

Thesaurus Entries

antecedent, anterior, chief, exordial, first, foremost, headmost, inaugural, inductive, initiatory, introductory, leading, opening, precedent, preceding, precessional, precursory, prefixed, prelim, preliminary, preludial, prelusive, preparatory, prepositive, prevenient, prior, proemial, propaedeutic