Oh, if you want a legal copy of 'Book Lovers', I usually start with the simplest route: your local library. Libraries plug into services like Libby/OverDrive and Hoopla where you can borrow ebooks legally with your library card. If the library holds the ebook, you can borrow it for a few weeks and read on your phone, tablet, or computer. Sometimes the file you get is an ePub or a Kindle format rather than a straight PDF, which is fine for most readers.
If your local branch doesn’t have it, I’d check ebook retailers next — Kindle Store, Kobo, Google Play Books, Apple Books, or Barnes & Noble. Buying a digital copy supports the author directly and often gives you instant access. There’s also Scribd and Audible (for audiobooks) if you prefer subscription models. And a heads-up: many modern ebooks come with DRM and aren’t offered as plain PDFs for copyright reasons, so expect ePub or AZW files. For research or historical texts, Project Gutenberg, HathiTrust, or the Internet Archive are great, but they won’t carry recent bestsellers like 'Book Lovers'. Personally I borrow through Libby when I can, or buy from indie bookstores online when I want to support the author, and that usually makes the experience feel better.