Skipping the introduction to a book, microfilm, or any record can create research problems and make brick walls even worse. Declarations of intent were destroyed in a 19th century fire in Hamilton County, Ohio. They were copied from the damaged originals and those copied records were kept and eventually microfilmed. A cover sheet indicated potential difficulties with the records.
If I had just skipped to the entry I needed, I never would have learned that it was believed that a significant number (never specifically stated) had errors.
And that was something I need to know.
Don't just jump to the index or the page you need. Authors don't just create introductions and prefaces to fill space.