[whitearrow]

So, as we know, there's no way, absent jailbreaking, to move sideloaded books from device to device without losing your collections. After a lot of trial and error, I came up with a way that's easiest, at least for me.

There are a couple of assumptions here:

-- You have a fairly limited number of collections. I have 20 total.

-- Most of my books are only in one (some two) collection(s) on the Kindle, plus "unread," if applicable, on the device. I use more tags in Calibre but not on the Kindle.

-- You manage your Amazon content using cloud collections.

-- You have some way to tell, on Calibre, if the book is from Amazon or not. (I use a custom checkbox, but file format can work, too, if you have sideloaded books in Mobi, or a tag.)

So here's my way of doing this:

-- Start by importing your collections onto the device, but don't download any of your Amazon books yet.

-- Plug the device into the computer and wait for it to appear in Calibre.

-- Click the tag of your largest collection, and if you only want to load your unread books, whatever your tag is for that. You want to do an "and" search here, like "fantasy" and "unread."

-- Sort the books so your Amazon books are separated.

-- Go ahead and transfer to device the "fantasy" and "unread" books.

-- Once the job is done, eject the Kindle.

-- Wait for the Kindle to show the books.

-- Go to List view.

-- On the top under the toolbar, pick "downloaded" "all items" and "collections."

-- Go to your Fantasy collection, select "add/remove items."

-- Again select "downloaded," "all items," and here is what's really important, "Recent."

-- Go ahead and select all the items you just added. All the books on the device should be in your Fantasy category now.

-- Now pick one book from Fantasy that you will remember and REMOVE it from Fantasy. Open the book, then exit. So you should see your categories and your one memorable book.

-- Reconnect the Kindle and pick another category. Repeat the steps above.

-- This time, when you add the new books to the category, the ones you just added will be first. Stop adding when you hit the memorable book.

-- Keep going until all the books you want from Calibre are added. Open your memorable book each time so you will know where to stop. You might want to take some breaks between collections for indexing (see Harry's post on this).

-- If you continue to go collection by collection, your newest books will always be the first ones in the recent sort, and much easier to find and add to that collection. You can do the same if you have different kinds of books sorted into different libraries.

-- Once I had all my unread books added from Calibre, I went and added all of these to my "unread" category. Skip if you don't have one. Then I tweaked, adjusting the books that were in more than one category so they were in the right place.

-- At this point, take another break to allow for indexing. Then you can add whatever you want from your Amazon books, which should already be sorted into the proper collections.

I hope this helps someone.