Walter R. Stahel is a person who thinks that we should use things more carefully and not throw them away too quickly.
Let's say you have a toy that you really love to play with. Instead of getting rid of it as soon as it gets a little old or you get bored of it, Walter thinks we should try to fix it or find a new way to use it.
That way, we can save resources and not waste things that are still good. It's like taking care of your things so they can last longer and you don't have to buy new ones all the time.
Walter believes that this way of thinking, called "circular economy," can help us be more sustainable and take better care of the environment.