I see questions on the Salesforce community forums quite frequently about concatenating a field value across all child records and dumping it into a field on the parent record. The most common use case is concatenating a picklist or text field value for all child records and displaying it on the parent record so that a user can get a bird's eye view of important data on the master record.

I looked into various tools and ended up using Process Builder and Invocable Method(Apex) to accomplish this requirement since that seemed to be the most elegant solution. If anyone else has dealt with it in a different fashion, please feel free to share in the comments below.

Hope it helps!

@The Blog Group 

Using Process Builder and Apex (Invocable Method) To Concatenate Child Record/(s) Information Onto Parent record