jobs-to be done: theory to practice
Its a theory to practice to build better products which revolves around the principle that focus on the jobs your product helps get done for your user rather than the product itself.
More or faster a product helps a customer job get done, more valuable the product is. It can generally be broken down in many other related principles such as "target the customers who will pay the most to get their jobs done best", "Spend R&D efforts to get a customer job done better or faster".
It emphasizes on the fact that products come and go, the underlying jobs-to-be-done doesn't go away.