As a publisher Random House supports all of the commercially available eBook formats in the marketplace. We generally publish all of our eBooks in all of the available formats.
If you have questions about ongoing format support for a specific purchase, we suggest that you contact the retailer from which you made the purchase.
If you have general questions about ongoing support for, or existence of, a particular format then we suggest you contact the owner of that format (e.g. Adobe, Microsoft).
For those of you inquiring about digital products with no encryption (a/ka/ drm or digital rights management) Random House has recently announced that our downloadable audio catalogue is available in drm free formats.
