I get why you're asking about the PDF — PDFs feel clean, searchable, and portable — but the short reality is: it depends on how that particular book or work was released. If the work you're calling 'The Thinning' was published under normal commercial channels, downloading a scanned PDF from a random site is usually not legal. Copyright law in most places gives the author and publisher exclusive rights to distribute digital copies, and unauthorized uploads on file-sharing sites or torrents typically violate those rights.
That said, there are plenty of legal routes to get a digital copy. Sometimes authors or publishers release
free pdfs for promotion, or an
older work might be in the public domain or under a Creative Commons license. University or publisher pages, the author’s official website, and legitimate retailers (like the ebook sections of mainstream stores or
library apps such as Libby/OverDrive) are the places to check. If a PDF is hosted directly on the publisher’s domain, or is explicitly offered by the author, that’s safe to download.
If you stumble onto a PDF on a sketchy site, beware: beyond legal risk, those files often carry malware, poor scans, or missing pages. Personally, I usually try the library or wait for a sale — I like supporting creators when I can. If it’s a rare or out-of-print title, contacting the publisher or author can sometimes turn up a legal digital copy. In any case, I’d favor the legal route both for safety and for keeping
good books coming my way.