If you have the technical background and is interested in a general and short introduction I strongly recommend Ethereum White Paper (https://ethereum.org/en/wh

If you have the technical background and is interested in a general and short introduction I strongly recommend Ethereum White Paper (https://ethereum.org/en/whitepaper/ https://ethereum.org/en/whitepaper/). Haven't went through it in a while, but I remember only having a clear understanding of how Bitcoin works after reading it.