It is a well-known fact that history books about major events like wars, riots etc will be biased towards the perpective or self-interests of the writer and one can only get a more balanced but not necessarily true version of what actually took place years ago by reading as many books as possible.
In fact if you were a player in the event, your version is already biased. So this story in malaysiakini about the Tunku's book can be useful but should not be taken as the definitive "be-all end-all" story.
All Malaysians will surely benefit from this sad episode in our history if all documents related to that incident were declassified and we allowed a panel of international historians to tell us more what happened during those bloody riots.
A Truth and Reconciliation Panel will also help to heal some old wounds and not just a self-interest group that is linked to the ruling party.