https://www.litesmith.com/lighten-up/

Best introduction to lightweight backpack we've found. Rather than talk about specific pieces of gear, it describes the change in mindset needed for ultralight backpacking. It doesn't tell you what to buy but guides you on how to decide what to buy. It's perfect for newbies or traditional backpackers who want to learn how to make the transition to a lighter, more streamlined approach.