Can Views output "raw" text field data? I have a view that shows the Body field of several book pages.  The text format for these pages includes the Markdown filter.

I want to export the body field data as the original markdown without processing it into HTML.  (This is an admin-only view that I want to use to collect the markdown-formatted text from several book pages to make an ebook.)

Is there an option within the Views module to output the "unprocessed" markdown?
Yes. Under the Rewrite results > Override the output of this field with custom text option, one of the Twig tokens you can use is {{ $FIELD_NAME__value }} (e.g. {{ body__value }}). This will have views render the field in its raw, pre-filtered, format.