From the action menu on any product details view you can open the review changes tool - it allows you to inspect the audit-trail for the product.
You will typically be able to see:
- WHAT was changed
- WHEN it was changed
- WHO changed it
The overview shows which command was used to effect a change, when it happened, and which user made the change. Click on an entry to see which changes were made specifically - you can see the original value and the updated value.