There is currently not a method possible to track such changs as who applied policies, etc., but you can turn on activity logging, and monitor who makes changes to a database, and when the changes were made.  By looking at the activity logging on the names.nsf, you can see who is making changes to the Address Book, this in turn will allow you to compare know activity to the date/time of the changes.

Here is an openntf project that might help you out (caveat....I have never used it)

https://openntf.org/main.nsf/project.xsp?r=project/7AB95E5906DED22E86257CDF001D0C6D/summary

Dear Bradley and Stuart,

Thank you both for taking the time to review and reply to my post.

I have configured Activity.nsf and checked out 'Change Tracking for IBM Domino Directory'. Seems like a very interesting auditing tool.

Security being a vital aspect in any company, Domino should consider including its own monitoring mechanism.