How Do I ReDownload Apple "Books" or "iBooks"? It's Dead in the Water.

*I am re-posting this question, as I was not allowed to edit my original entry. Go figure*

How can I download "Books" to my recently Mojave updated imac? The icon is dead and doesn't open and the icon is the generic icon for application and not the Books icon. Do I have to completely reinstall Books, inorder to fix this?

I cannot find neither "iBooks" nor "Books" in the apple store.

Where is the software store these days on the Apple site, anyway? Is everything being herded to the App Store?

Also, I tried following the instructions regarding redownloading an Apple application by first trying to delete the app in question as per instructions so that it will show up in the app store as a recently purchased or application available for download. This I am unable to do as the error message telling me that it is required by the operating system therefor it cannot be deleted or moved to the trash appears.

I am at a loss here. It has completely wasted my morning on what was supposed to be a simple thing.