This document provides an introduction to blockchain technology and cryptocurrencies. It discusses the origins of blockchain in Satoshi Nakamoto's 2008 whitepaper proposing Bitcoin as a peer-to-peer electronic cash system. It then outlines some key aspects of blockchain including how it uses cryptography and proof-of-work to form an immutable record stored across a distributed network without a central authority. The document also briefly reviews topics like cryptocurrency mining, smart contracts, initial coin offerings (ICOs), and the current state and opportunities of blockchain applications.