This document provides an overview of blockchain basics and distributed ledger technology. It introduces key concepts such as distributed ledgers, blockchain categories of public, private and hybrid, and the scalability trilemma of balancing decentralization, security, and scalability. It also outlines the different components that make up the "crypto flower" framework including distributed systems, cryptography, governance and economics. Finally, it discusses the various roles within the blockchain ecosystem such as users, miners, validators and developers.