Look at the anchored post above titled "Mastering the Nikon D800 NikoniansPress/RockyNook Book" by Darrell Young, Digital Darrell. It is written by a long time Nikon shooter who has written several books about Nikon dSLRs. There are many reviews here and you can look inside at Amazon.com or if you have a B&N Nook eReader download a sample. There are also reviews and comments in this and other camera forums about this book.
This book is available in paperback and eBook formats. O\'Reilly Media offers a special price for purchasing both the eBook and printed version at one time and also has an update service or list of errata for registered owners.