This is a bit of a challenging way to do it, the content will be accessible only through select tablet and mobile devices: Apple iPads; the Amazon Kindle app for Apple mobile devices, Kindle Fire tablets, Nook HD and Tablets*; and the Google Play Books Reader for Android and Nexus devices. And there's this key phrase attached to all that: "Functionality of the audio/video content is subject to your eBook device. Check the store listing on your favorite eBook retailer site to find out whether your device is capable of playing audio and video elements."
*- Note that in attempting to use the Kindle app on my Android tablets, there was fairly clear notice in each eBook that enhanced audio/video content was only going to work on Apple devices and Kindle Fire devices (this is almost certainly due to rights management), so I was forced to seek it out on the Google Play Books store where the only mention of compatibility is "video may not play on all readers. Please check your user manual for details" in which there are, naturally, no such specific details.
If I may editorialize a little bit... Fans are going to suffer over this decision. This is a very challenging way to share this type of content, and author J.W. Rinzler says that it's only 95% complete, the last 5% simply couldn't fit inside. One might say that this is pretty frustrating, it leaves out a lot of fans entirely, and it's difficult to figure out which app will play the content on which device. It comes off as a digital rights management get-rich-quick scheme. It's also very frustrating for those who are cross-platform users, someone who owns Apple and Android can't buy it once and use it on both with a single purchase (Amazon could have made this possible via their Kindle app but hasn't gotten their media rights up to minimum specs for Android).
And that's to say nothing of the fact that it penalizes those who spent $85 cover price for each of the hardcover books. That's just bad business sense, that's double-dipping in the worst possible way, and the fact that they waited until after the hardcover came out before revealing this news smacks of callous moneygrabbing.
But having seen some of this content at Comic-Con, I can attest that this is some of the most amazing behind-the-scenes content I've ever seen from the Star Wars trilogy. Each enhanced eBook comes with around half an hour of video and 15 minutes of audio uncovered by Rinzler during his poring over the Lucasfilm archives to create his fine Making Of series. Much of the content in these enhanced eBooks was thought lost forever, check out the Complete List of Contents in this article on StarWars.com and tell me you aren't drooling over the thought of hearing and seeing these things. Any Star Wars fan should recognize the inherent value of this stuff, minutiae for sure but the kind of little stuff that makes a fan's heart skip a beat in excitement.
The price of each enhanced eBook is list $18 a piece, Amazon has them for the aforementioned Kindle app (only enhanced on Apple devices, Kindle Fires, and Nook HDs) for $12.99 each; iTunes has them for Apple devices for $12.99 each; and Google Play has them for the Books app for $14.39 each. Prices are likely to keep fluctuating, but expect around $15 per enhanced eBook.
Screenshot taken from my Samsung Galaxy Tab 8.9, note that screenshot has been shrunken and JPG quality has lessened the true quality, but you get the basic idea, it's a book page with a playable video.
Since I was eventually going to buy it anyway, I picked up the Making of ROTJ as research for this article. I got it on Google Play - my only tablet is Android - and immediately was playing a video I picked randomly from the middle of the book, it worked perfectly. I then went to my Android phone and played it there as well, no problems at all, the content was even streaming since the whole eBook is over 300mb.
The best thing though is that this "enhanced eBook" isn't just a bunch of new content dropped into the back of the book, it's included as part of the reading experience, it's put in the places where it's appropriate, it fits with the text on the page, and that's what makes this "enhanced eBook" thing matter and why fans should strongly consider buying these eBooks even if they already own the hardcopies.
As Apple puts it in their iTunes Store listing, "[this] enhanced multi-touch eBook [...] transforms The Making of Star Wars: Return of the Jedi into an immersive multimedia experience."
That's exactly right, and it's something you couldn't get from just 3 folders of files or even from "Star Wars: Behind the Magic" CD-ROM-style experience, it's the richness of the context which makes being an enhanced eBook matter, and it's why fans should not dismiss casually despite the notable challenges of being only available on mobile devices. Would you have paid $45 for the content anyway? Probably. So if you have a mobile device, and the patience to figure out which platform works on what device, then this is a ultimately a recommended purchase even if you already own the books. And if you waited to get Making of ROTJ in hardcover, save yourself the back-breaking labor (the physical hardcover books are massive) and just read it on a tablet, saving yourself around $70 and gaining a lot of extra content.