First of all, I have appreciated a lot the content of this book. It has gave me a good overview on MOSS 2010 possibilities (with sometime a lot of details).
, I found a very small bug in the sample code in the book (chap 10).
In fact, in the example for the creation of a customer Document ID provide, you proposed a sample to deploy the feature in Sharepoint with a EventReceiver.
In the method, "FeatureActivated" :
To set the new provider there is a mistake in the second parameter:
it's not : Documentid
it's : Documentid
.SetProvider(sitecollection, new CustomerDocumentIdProvider