I have an ebook that I've created in the ePub format. I'm fine with people copying, printing, and sharing the ePub. What I'd like to avoid is readers editing the content. Is there a way to accomplish this?
No.

But you could make a checksum of the ePub, place that on your web site, and then readers can check that they've got an unaltered version.
Thanks Grand Mouse!
That's an excellent solution.
I appreciate your help.
That is an excellent idea. One tiny caveat, changes stored inside the epub container itself by bookmarking or annotations done by some e-readers (and calibre itself?) would make the checksum test fail. But if it is to ensure fresh copies are identical then all is good.
@KevinH - Understood. That's useful information to consider. I'll bear it in mind.