Disclosure: I haven't read the book. However, it certainly has received some good praise, and it's about as timely as humanly possible.
The name of the book is "The War on Cops: How the New Attack on Law and Order Makes Everyone Less Safe." There's an excerpt at Freebeacon.com which addresses Obama's embrace of the false media narrative of the Ferguson, Missouri, encounter Michael Brown had with the police. Here's a brief excerpt from the chapter excerpted there:
This kind of misinformation about the criminal-justice system and the police can only increase hatred of the police. That hatred, in turn, will heighten the chances of more Michael Browns attacking officers and getting shot themselves. Police officers in the tensest areas may back off of assertive policing. Such de-policing will leave thousands of law-abiding minority residents who fervently support the police ever more vulnerable to thugs.
Obama couldn’t have stopped November’s violence in Ferguson with his address to the nation. But in casting his lot with those who speciously impugn our criminal-justice system, he increased the likelihood of more such violence in the future.
President Obama didn't pull the trigger on those police officers in Dallas. But his racial divisiveness certainly didn't do anything to quell the violence. It's as if he wants a certain segment of the population fired up and ready so he can use that force for political will.
Meanwhile, Black Lives Matter paused to take a breath after the "lone gunman" killed the police officers in Dallas. Then they carried on as usual. War on cops, indeed.