It’s a Double whammy of Kamen Rider W merch today, to go alongside the updated Seihou Fang Joker info from earlier, P-Bandai has a left-field announcement for us with a replica of the blank book Phillip uses to gain access to the Gaia Library in the show.
One page of the book will contain a quote from the character aside from that, no other release info is known. Pre Orders for this product will begin March 2018.
Update:
Thanks once again to @_erasu the book will apparently come with two covers: The Phillip’s Book cover and a Joker cover. In addition, a bookmark in the shape of a Gaia memory will also be included.