If you're hunting for a legal eBook of 'Left Behind', the quickest path is the usual storefronts: Amazon Kindle, Apple Books, Google Play Books, Kobo, and Barnes & Noble's Nook store all sell digital copies. I often check Kindle first because of its frequent sales and the ability to read across devices, but if you prefer DRM-free files or a different ecosystem, Kobo or Apple Books can be friendlier. Also peek at Audible if you want the audiobook — sometimes bundles or narrated editions make the experience feel fresh.
Beyond retailers, don't forget the publisher: the series is handled by mainstream Christian publishers, so the publisher's website sometimes links to legitimate editions, box sets, or special promos. If budget's a concern, your public library is a goldmine — use OverDrive/Libby or Hoopla to borrow the eBook or audiobook for free. Availability varies by region, but borrowing through your library is 100% legal and feels great when you want to sample without committing to a purchase. I usually check the library app first, then hunt sales, and if neither works I consider buying used print if I'm collecting physical copies.