Some other step needed?

Book post is actually an input filter so there is an extra step after enabling the module. After enabling, go to Administer->Site Configuration->Input Formats. Click on HTML Filter or Full HTML (or both) and check the Book Post Module box. When you post some content, check under the input format and you should find a line that says, "An ISBN or Open Library ID between curly braces {{}} will return book info and cover."

Let me know if that does the trick.

"When I enter an ISBN in the body of a post in double curly brackets and save, it returns:
No record found for Marc mid:
Marc record did not load when No marc data exists, trying to use nid.
even if I use an ISBN from a record on the Open Library site."

I'm a little confused by this. Are you using the MARC module? If so, it's possible that the two modules are clobbering each other. Hopefully the above will do the trick.

I'll add a README file in the next release.

That did the trick -- thanks!

I do have the MARC module on the site (test-driving it). Not sure if there is a conflict, but once I set the input format as directed, the books come up just fine.

Can this detail to be added to the home page and a read me added to the module? Thanks!