How exactly did Einstein establish the theory of relativity? What is the relationship between ether and relativity? What role did the Michelson-Morley experiment play in the process of establishing relativity? Why is it hard to reconcile the principle of constant speed of light and the principle of relativity? Are length contraction and time dilation merely visual effects? Is the mass-energy equation E=mc2 only valid in nuclear reactions, and how should we correctly understand this equation? The author approaches these questions from the perspective of beginners, using simple language and rigorous logic to guide readers into Einstein’s intellectual world, allowing secondary school students to freely explore the world of relativity.