I bought the Manga Guides to Databases and Statistics, and they were both fairly good introductory guides to their subjects. I don't know about the Cartoon Guides, but the Manga ones have a mix of (sometimes incredibly contrived) story and more textbook-y content, and they are interesting and reasonably varied. The MG to Databases, for example, is set in a magical kingdom where the princess is having trouble dealing with inefficient processes in the sale of apples, until her father sends her a book that contains a "Database fairy", whereas the MG to Statistics has a teenaged girl asking her father to get one of his employees to tutor her in statistics, thinking she'll get the good-looking guy from the first chapter but winding up with a glasses-wearing geek instead.
Has anyone else bought or read any of these? Any good ones or ones to avoid?