Cassandra Clare shared some info about the reading order of her next series, after a fan asked.
This is what Cassandra said:
When you have a situation where you are writing different books that each focus on different characters, there will always be factions that want their preferred book to come out first. There are those who would prefer to have the first Last Hours book published next, or Queen of Air and Darkness, or The Golden Tower (which is actually my next book: Sept 11, 2018). You can never, ever make everyone happy. All you can do is figure out the schedule that works best to create the highest quality books you can.
Still, a few things:
Both Ghosts of the Shadow Market and The Eldest Curses are collaborations with different people who have a variety of commitments and work situations. While my publisher has some control over the publication schedule for these books and stories, there are other people’s schedules and work habits to take into account as well.
There is a general belief that publishers just put out whatever book they get handed in the order you hand them in, but it isn’t really like that. The first Magnus book was already handed in; it’s in rewrites, and the second draft is being handed in months before the first draft of Queen of Air and Darkness. That doesn’t mean it’s being published before Queen of Air and Darkness. It’s being published after, in part because the Dark Artifices series has sold well and my publisher believes strong sales of Queen will lift the sales of The Eldest Curses. They also believe I will be able to promote Eldest Curses when I go on tour for Queen, and since they regard TEC as something of an “unknown quantity” they want it to have that help. Publishers do actually have strategies (well, some of the time.) That’s why they want the first Malec book out in March, 2019. As I said before, they picked that date, just like they picked the date for Queen. They are not going to move it any earlier, and Ghosts of the Shadow Market is irrelevant to that. In fact, if you work in publishing, the idea that my publisher would push one of their scheduled books back because I was self-publishing a bunch of novellas is hilarious. They would never.
Also, the reason Ghosts of the Shadow Market is coming out so soon is that the stories are online only ebooks. Printing and distributing physical books takes months. Books are typeset, printed overseas, and literally shipped back to America on planes and boats. An ebook requires no physical handling. Once an ebook gets through the editing and design process, it can be uploaded in an hour. That is a huge difference. There is also going to be a print version of Ghosts, and because of the physical handling required, it will of course be published after TEC#1.
I’ve also seen quite a bit in terms of questions as to whether the content of the short stories is going to be different because they will not have “publisher oversight” – I actually don’t know if that means “Will Ghosts contain subliminal messages or porn?” or what, but the answer is that you won’t be able to tell any difference between these stories and the ones in Bane Chronicles or Tales from Shadowhunter Academy. They are being self-published in the US as e-stories, yes, but 1) they are being edited by Gavin Grant at Small Beer Press, which has won multiple awards, so he is unlikely to let them sail off the rails and 2) they are being traditionally published in hardcover by the same publishers who publish all my other books, including Bane Chronicles and Tales from Shadowhunter Academy. In fact, they are even being traditionally published as ebooks everywhere outside the US. So if you are hoping for robot sex or something, that is unlikely to happen. *beep beep beep*
All of that is to say: these two projects have literally nothing to do with each other. If Ghosts of the Shadow Market was suddenly cancelled, it would not move The Eldest Curses up even one day. I hope you can enjoy both projects without imagining they are somehow getting in each other’s way!