I've had several writers recently ask me how I got the book titles bolded in the description for JULIUS KATZ AND ARCHIE, and the way that was done was using Amazon's Author Central instead of their KDP (Kindle Direct Publishing) pages.
Author Central is just a much better way to enter you ebook description. You can bold and italicize text, and you can enter in a lot more information than you can from the KDP method. For example, using this approach you can enter 4000 characters for the book description, then another 8000 characters in the 'From the Back Cover' section, which is a good place to put blurbs for your book, as well as blurbs for other books.
You can take a look at my JULIUS KATZ AND ARCHIE page to see how much better this can look than using KDP.