Best format for authors to submit documents for a book collection?

I guess this is a proper topic if you're using InDesign to collate and produce the EPUB...

Word is pretty much the universal standard; if they choose to use Google Docs or Pages or whatever, all of those will save in DOC or DOCX format. I'd request submissions in DOCX or RTF (the bare-bones, exchange format used by Word and other apps).

I'd also do all the collation, editing and basic formatting in Word, as it's a far better long-document manager and editor than ID.

Your final version, ready to be imported into an InDesign document for formatting and layout, should —

• Have no spot formatting whatsoever.
• Every paragraph should have an assigned style (preferably not including "Normal" — create a specific body text style and devolve things like bullets, inset quotes and the like from it.
• Any inline formatting such as bold or italics should ideally use a character style named something similar but not identical (Bolded, Italix, etc.) ID will interpret standard bold and italic properly, but as spot formatting over which you will have no control.
• Keep the number of styles to a minimum, and make them appropriately hierarchical. Heading 1 should be the source style for Heading 2, which should source Heading 3, etc. Your body format — let's call it Body Text — should be the source for all other body formats such as bullets.
• Don't fuss too much with the exact look and layout in Word. It's more or less a 'manuscript' and you will be able to completely change the styling and details in InDesign. (You cannot, though, much control the look and style in ID with what you do in Word, so it's best not to try too hard.) Getting appropriate styles assigned to each paragraph and each instance of inline formatting is the goal.

Along with spell-checking, editing and (important) removing ALL instances of more than one white space. No double spaces, double paragraph returns, double tabs or any combination such as tab-space. (Tabs don't make it into EPUB anyway, so don't use them.)

This should produce an ideally clean and "vanilla" document for formatting and layout in InDesign. I assume you're aiming for a reflowable EPUB, so once you get there you will need to make certain choices about the structure and formatting options. You may wish, for example, to put each story in its own INDD file and manage them using a Book; this has a few advantages for content formatting over a single document file.

And while EPUB goes directly to Kindle, there are some significant differences in how the readers handle content, so it's either "choose one" or plan to have two differently formatted source documents, one for EPUB-as-EPUB and one for EPUB-into-Kindle.

You'll have more questions. We'll be here to answer any we can. 🙂

—