[DSpider]

Regardless the scanning method (document feeder, flatbed scanner, compact camera, mobile phone, etc), after you scan a book you should take a few minutes to look through the images and see if it skipped any pages. Especially with automatic document feeders. You never know...

Anyway, I think the scanning part is the easiest. Processing the scans takes much much longer: OCR-ing with FineReader, proofreading in FineReader, tracking down the fonts (or at least their closest match), vectorizing the cover and/or any other images in the book, doing the layout in Word, saving as PDF, optimizing the PDF, proofreading the final product... Add to that converting the Word file to HTML, loading it into Sigil, manually cleaning it up, stylizing it, saving as ePub, converting it to Mobi... Yeah. The scanning part is definitely the easiest. But I guess it depends how far you wanna go.