How do I show all "songs" that reference an "album" (for example)?
Thanks for this comment pointing me to the EVA module.  Here are the exact steps I had to take in Drupal 8, which is slightly different than Drupal 7.

Steps for Drupal 8:


Make sure your reference field is already set up (e.g., the Song entity has a field referencing an Album)
Install and activate the EVA module
Add a new view (Manage > Structure > Views > Add View)
Type in the view name, and in View Settings, set it to show Content of type Recording (i.e., the "child" entity).  No need to "Create a page" or "Create a block".
Under the Displays heading will be a label called Master.  Click the Add button just to the right of that.
Select "EVA", not "Entity Reference" (this is a difference from Drupal 7)
Under Displays > Format, I like to change "Unformatted list" to "Table".
Under Display > Entity Content Settings, change "Entity type" from "None" to "Content".
Change "Bundles" from "All" to "Album" (i.e., the "parent" entity)
Under Advanced, add a "Contextual filter".
Search for the field which links Recording to Album (i.e., the field in the child entity which references the parent), and select it, and click "Add and configure contextual filters".
Under "When the filter value is not available", select "Provide default value" and choose "Content ID from URL".
click "Apply".
If you know the ID of an album (parent entity), you can enter it in the parameter in the "Preview" section to make sure it is working as expected (you will need to pre-populate entities to test this).
Click "Save" under the "Display" section for the view.
A message should show up: "The view ___ has been saved."
Clear all caches (Manage > Configuration > Development > Performance > Clear Cache > Clear All Caches).
Navigate to a sample parent entity, and the child entities should show up on that page.