Sometimes you might want editors to be able to edit only a couple of blocks on your site. After all, granting them access to the entire Structre >> Blocks page can potentially overwhelm them as well as give them a chance to really jack things up.
The Block Access Module gives granular control over which blocks a specific role has access to. The developer can even control which pieces of the block the editor can access. (i.e. Only the body and nothing else)
Once you enable this module you, when you go to edit a block (as admin) you have new options. For my situation, I only wanted to grant the "Content Manager" role access to edit the Body field so this is what I did. I did this for only 3 blocks on my site.
Now, when the editor who has the 'content manger' role hovers over the top right of only those specific blocks they will see this:
"Administer block access" should NOT be checked for the editor/content manager role
"Use Contextual links" SHOULD be checked for the editor/content manager role