MsML (MacQueen’s successor ML) is proposed as a successor ML. MsML is an exercise in micro language design, being a dialect of (Standard) ML. It carries on from the language revisions included in the 1997 Definition of Standard ML (Revised), but is more radical and less backward compatible with SML ’90. MsML was developed as the target language to be implemented in a personal project to write a new front end for the SML/NJ compiler.