I have a very simple report, which lists the Summary MIN and Summary MAX values of a field in a table.  It is displayed in a group header. 

I am not understanding how to also list a second field (a date and time field) next to the corresponding MIN or MAX displayed summary value in the same group header row.

Can someone shed some light for me?

Thank you in advance. 

Rather than using Min and Max, you could sort your data on the value field (Sort, not Group!).  You would need a group on another field.  You then put the value and the date in the group header and the group footer.  This will give you the min and max values and the dates because the smallest value will be available in the group header and the largest in the group footer (or vice versa if you sort descending.)