I've been searching, and the book "came" out, but I can't find it. For example, on the amazing amazon the third edition I can buy, and I can find the fourth edition which is not for sale, or is for sale for a ludicrous cost.

Jessica Mckellar is the author, and after some Googling I found her github with the Linux Device Drivers 4 source code!, and after reading through some of the Git commits I found that the repository is a clone of LDD3's code, but scrolling through the commit log shows updates / some modernization of certain examples, and some new content being injected into some sections. I found a older twitter post with a link to the books O'Rielly listing. Unfortunately the link she posted has a 404 currently. But I found an archive of that link in July 2015 (it should be out by then). While it is possible to pre-order, the books release date got pushed to November. After that, it got pushed another year. I tried my best to find archives around November 2016, but all I could find thats close is this which states November 2017, and after that the page went 404.

So I bring all of this (perhaps slightly creepy?) research asking where is the 4th edition? Did it get abandoned? if so, why? It does look like this, but perhaps another author is picking the project up? Maybe I'm really out of the loop, but did Jessica say she stopped working on it? Perhaps people who have Twitter could reach out to her or any of the authors / send this post and see whats the status of the book?

Thanks everyone :)

Edit: Continued looking, I'll broaden my scope beyond Jessica McKellar because upon second glance of the cover there's Alessandro Rubini, Johnathan Corbet and Greg Kroah-Hartman as authors. I'll look some more and see if I can find anything else.

Edit 2: Found some stuff, I would still want an explanation as to why but I bring to you more links. Using a custom search (searches only reddit, and match only the phrase I provided, not keywords) I found this Reddit post from a presentation Greg did, aparantly he says there will be no 4th edition. So yes! I have a lead! Next I fed Greg's Reddit username into a wonderful tool that searches a redditors comments, I found a comment where he said that he knew nothing about the 4th edition. Keep in mind this comment is 2 years old, but at the time of posting it would be January 2nd 2015, within months of one of the first release dates. Now alot can happen between then and the further release date(s). Sadly, no why factor from any of the "authors".