How should I interpret a book editor not responding to me after accepting my chapter proposal? I had a detailed chapter proposal accepted about five weeks ago for a collection of critical essays in my field, edited by a retired professor who has been prolific in publishing while retired. In the acceptance email, the editor stated that &quot;in the coming days,&quot; we'd all receive further information about our specific chapters. I replied to the acceptance email shortly thereafter, saying I appreciated it and was looking forward to receiving the information.
About ten days ago, having heard nothing, I sent a polite, concise follow-up email in which I requested clarification on the timeline/details of the chapter and reaffirmed my interest. No response.
A few days ago, I left him a polite, brief message on his office phone, identifying myself and providing a number of ways to reach me--hoping one might be easier than email. No response to that so far.
So all I have in hand is this initial chapter acceptance. I'm confused, a bit frustrated, and a bit worried. The CFP stated that initial chapter drafts were due in August.
My questions:

What should I do at this point? I need to plan my workload for the summer, and if I'm still a part of this project, I'd need to set aside significant time to complete it. I really want to complete it; I'm passionate about the proposal, and the book looks like it's going to be great.
Is it reasonable for me to assume that I've been booted from the project? Does it ever happen this way, where, after an initial acceptance, someone changes their mind and simply stops returning all communications?
I realize there's a possibility the editor is in fact slow, suffering a health/personal setback, or facing some other obstacle. But in this case, given my previous attempts to contact them, how should I proceed?

Some pertinent points:

The editor of the volume and the press are both well-known and (as far as I know) well-regarded, or at least ubiquitous in the field. They're not cranks or unknowns.
The acceptance email was a mass email, and me and the other accepted authors were all BCCed, so I can't contact one of them to ask if they've heard from the editor.
If I don't hear from the editor within some timeframe over the coming months, would it be reasonable to contact the volume's publisher or the editor's colleagues, asking if they know (a) whether this person is OK (not injured or worse) or (b) a way to get in touch with them?

Thanks for providing advice to a junior scholar here.
Your clock is running faster than their clock. They have a lot of people to coordinate with and a lot of editorial work, I suspect.
This isn't the only publication they are dealing with, most likely. And if everyone is sending them mail every few days it just bogs down the process even further.
It may even be a good thing that it is taking time. A predatory publisher would be after you quite quickly for payments.
Perhaps you should just relax.