I want a statement on each record that says: Last Modified on (date) by (user). The date bit is easy - I just set a field to auto enter the date of the last modification and use that. But how do I capture the account name of the last modifier of that record, and get it updated in the second (user) field? I've tried using a calculation field with Get(AccountName), but this simply records the account that created the record, not the last user.

It's got to be a simple job, but my head is spinning.....

Another auto-enter option is Modified By. If you need to capture each modification, then you're looking for an audit log technique.