The above photo is somewhat illustrative of the number of people involved in getting your book to market. Even if you self-publish there are still many functions that you may have not done yourself.
Below is not an exhaustive list but a rambling stream of consciousness when thinking about the people who are involved in the publishing process:
Author (kinda important)
literary agent (we think this is kinda important too)
acquisitions editor
contract department (legal)
substantive editor
copy editor
proofreader (more than one?)
managing editor
production manager
ISBN agency
typesetter
cover designer
art director
interior layout designer
copy writer (back cover and catalog)
printer (a full team involved at the printer)
warehouse team
copyright office
chief financial officer
marketing director
publicity personnel
sales manager
sales people (multiple in every publishing company)
special markets sales person
foreign rights manager
subsidiary rights manager (often the same person as above)
accounting
SEO manager (digital strategies)
metadata data entry (double check all the details)
online store coordinator (each “store” a different person)
brick & mortar store buyers
online or in-store merchandising manager
ad designer
Add any that I missed in the comments below.
By the way, none of the above jobs are done for free. Thus the challenge of the economics of publishing.
If everything works well the group can create this picture: