This book is a great read and an invaluable reference to Data Guard. As a production DBA working on a 10g RAC cluster with RAC/Dataguard standby I now keep this book on my desk at all times. Although it was written for 11g there are many pointers to how things worked in 10g. Quite a few of the tips and tricks truly are not documented, e.g. multi-threaded gap resolution in particular which saved the day for me recently when our standby became 5 days behind the primary database due to a power outage! I can't say I'm too surprised to find this is a great book as I've often heard Larry Carpenter speak at the Oracle User Group conferences, and it's clear that there is probably nothing he doesn't know about Data Guard. My only criticism is that sometimes assumptions are made, e.g. in the creation of a physical standby it assumes you are using an spfile. But on the whole it was worth every penny!