I don't think I ever heard about anything like dbook though.
There definitely was a project on the STEEM blockchain called dBooks, and it's still listed at steemprojects.com, but the website dbooks.org appears to be down.
The last update from the founder was over seven months ago, when he talked about taking dbooks to the next level, after having 72 books printed there and over 1,000 reads.
That, however, seems to be the last of the posts. The time period corresponds with the beginning of the bear market, so maybe that contributed to a stoppage of things.