Michael Armstrong-Smith's latest book, Oracle Discoverer 10g Handbook, co-authored by his wife Darlene Armstrong-Smith, updated for Discoverer 10g, and based on the 10.1.2.45.46C release, is out due later this month. Michael tells me that the book is with the printers, and that McGraw Hill is expecting the book to come back shortly. Therefore it should start shipping by the end of the month, or sooner.
You can view the book details on Michael's web site (link to site) or on Amazon.com (link to Amazon.com).
The book, apart from being extensively updated for the 10g release of Discoverer, has separate chapters for Discoverer Viewer, Discoverer OLAP, and Discoverer Portlets.
Mark Rittman (link to Mark's blog), Oracle BI & DW expert and Oracle ACE (link to Mark's ACE profile), has written the chapter on Discoverer OLAP.
Over the next few weeks I shall be posting more details about the book, including excerpts from different chapters (I acted as technical editor to the book, so I have some knowledge of the book and its contents :-). The biggest update to Discoverer in a long time now has the best and most comprehensive book to go with it.