I read it a while ago and was so impressed I immediately applied it to my next project. Currently the project is half-way through and bang on track, even though we have suffered setbacks and unexpected problems. Riskology helps you to expect the unexpected (although perhaps not the Spanish Inquistion ;-)
I was hooked as soon as I read...
"...if we know nothing else about your project or your organization, our safest bet is that your original size estimate...will cause you to overrun your schedule by more than a third"
How many projects in your organization have overrun their schedule by a third right now?
I am currently only applying a fraction of the wisdom in the book to my project, but it is still helping enormously.