This document provides an overview of critical thinking skills for UX designers. It discusses how critical thinking is not about tools but the thinking process that leads to tools. It encourages writing an "obituary" for your ideas to test their viability. It explores concepts like the limbic system in the brain and different thinking shapes like 'Z' thinkers who reframe problems. It advocates understanding context, current problems, and desired outcomes. It presents design thinking activities like role playing a browser, seeing through different perspectives, and using classical invention techniques. The overall message is that critical thinking opens up new opportunities by solving problems in novel ways.