Related to https://pharo.fogbugz.com/f/cases/2919/should-remove-TimeStamp Independent from the actual name (TimeStamp/Timestamp is shorter), it is confusing to have the two. TimeStamp inherits from DataAndTime and adds only the following: (1) its #printOn: is different (2) its class side #readFrom: matches this (3) its nanoseconds get set to zero on creation (4) it has some additional API ([plus|minus][Days|Seconds]:) (5) it has some alias methods (date, time) TimeStamp seems to be primarily used to deal with method timestamps. [A] Now, (1) and (2) for its primary usage [A] could easily be moved to DateAndTime. (3) is questionable and could be solved by #rounded, if really needed. (4) is plain silly (5) is dangerous, the originals are better So instead of moving API from TimeStamp to its superclass DataAndTime, I would remove it ;-) Comments ? Sven PS: Zinc did use TimeStamp in some places, but replacing all occurrences by DateAndTime had no effect, they are equivalent.