Gives some strategies on how to be more effective in your first 90 days at a new job or in a new position. I couldn't finish it. I found it much too academic. He also repeatedly conveys the idea that the optimal approach will depend on your situation. It didn't give any useful tips, it just presented common sense ideas like "network with the people - they'll know the culture," "don't change too much too fast," "find people who will support you and make sure you support your boss."
It doesn't need a chapter by chapter breakdown. I didn't think it was that good. If I were a VP moving to be a CEO then it might be useful. I think that for most of us it will not be helpful.