I recently had to make a physical book that was long out of print accessible for someone using an iPad for single-switch-accessed reading. With the help of a colleague at Disability Services at Dundee University I ended up with a PDF file with embedded OCR information that should allow the reader for example to adjust the font size in the reading app. However, in order to access the underlying OCR information, you need to convert the document into the Kindle format. You can do this by placing the word ‘convert’ in the subject line of the email with the attached PDF that you send to your Kindle app. You can find the app’s email address under Settings in your app – but don’t forget to register the email address you’re sending from on the Amazon website first (under: Your Account/Manage your Kindle/Personal Document Settings/add a new approved email address). Good luck!