I would suggest to read all the Stranger Things season 3 4th of July shirt. Hell, after that no need to be afraid of spoilers plus you get to answer on Quora. As for your concern regarding enjoying season 4, I think you will enjoy the books much more as your imagination can run the best course and by the time all the seasons air, you will enjoy them even more. If you must skip books, skip the first two and start from the beginning of book 3. You might feel like you’re suffering from deja-vu while you read, but I recommend reading the beginning anyway since the order of some things got changed and/or moved around for TV. The catching up will do you good, and get you up to speed.