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description: Lesson 1 Introduction
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# Lesson 1: Outline

#### Part 1: Overview of Ethereum and Smart Contracts

**Ethereum Basics**

* **What is Ethereum?**
  * Ethereum is a decentralized, open-source blockchain system that features smart contract functionality. It's a platform for building and running applications without any downtime, fraud, control, or interference from a third party.
* **Decentralized Applications (dApps)**
  * dApps are applications that run on a peer-to-peer network of computers rather than a single computer. They are outside the purview and control of a single authority.
* **Ethereum Virtual Machine (EVM)**
  * The EVM is the runtime environment for smart contracts in Ethereum. It's a quasi-Turing complete machine; the quasi part comes from the fact that computation is intrinsically limited through gas.

**Smart Contracts**

* **Definition and Purpose**
  * Smart contracts are self-executing contracts with the terms of the agreement between buyer and seller being directly written into lines of code.
* **Role in Ethereum**
  * In Ethereum, smart contracts are treated as autonomous scripts or stateful decentralized applications that are stored in the Ethereum blockchain for later execution.
* **Applications**
  * Examples include voting systems, automated DeFi services, identity verification, and more.

**Ethereum Networks**

* **Mainnet vs Testnets**
  * The Mainnet is the main network where actual transactions take place on the distributed ledger. Testnets like Ropsten and Rinkeby simulate Ethereum network conditions, allowing developers to test without using real Ether.

#### Part 2: Introduction to Solidity

**Solidity Overview**

* **History and Development**
  * Solidity was proposed in 2014 by Gavin Wood, and later developed by the Ethereum project's Solidity team.
* **Why Solidity?**
  * It's designed to target the EVM and is the most mature language for writing Ethereum smart contracts.

**Basic Syntax and Structure**

* **Structure of a Solidity File**
  * A typical Solidity file starts with a `pragma` directive indicating the compiler version, followed by contract definition.
* **First Smart Contract: Hello World**
  * A basic contract in Solidity starts with `pragma solidity ^0.8.0;` (or the version you are using).
  * A contract is declared with `contract HelloWorld { }`.
  * Inside, you can define a function to return a string.

**Part 3: Development Environment Setup**

**Setting up Solidity Development Environment**

* **Tools and IDEs**
  * Remix IDE is a powerful, open-source tool that helps you write Solidity contracts straight from the browser.
  * For a more integrated environment, Visual Studio Code with Solidity extensions is recommended.
* **Introduction to Remix IDE**
  * Remix is a browser-based IDE that provides an environment to write, debug, and deploy smart contracts.
  * It supports both Solidity and Vyper.

***

This lesson is your first step back into the Solidity world. Take your time to understand the basics and get comfortable with the environment and the language syntax. Once you've completed the exercises, you'll have a basic but solid understanding of Ethereum, smart contracts, and the Solidity language.
