# Content Overview

Eth2 is a sprawling technical undertaking with countless moving parts. In creating an educational resource about this subject, we've spent significant time and energy developing a content flow intended to make Eth2 accessible to a wide and diverse audience. Here's a taste of the topics covered within this book.

# The Basics of Consensus

This book begins with an exploration of consensus, the process by which networks of computers can come together to make decisions. Eth2's new Proof-of-Stake consensus protocol is in many ways a return to more traditional ideas in the world of consensus theory. Understanding these core concepts is critical to understanding the limitations in which Ethereum's consensus protocol exists. In The Basics of Consensus we take a look at the origins of modern consensus mechanisms. In particular, we're aiming to build up a knowledge of the concept of Byzantine faults and state machines. These two key ideas lay the foundation for Ethereum's development.

# The Origins of Blockchains

The leap from consensus mechanisms to blockchains isn't particularly obvious. In The Origins of Blockchains we try to understand how "old school" consensus theory gives rise to the idea of a blockchain when applied to digital finance. We'll see how many of the ideas we now take for granted (like Proof-of-Work and the concepts of "blocks" of transactions) came out of the desire to create effective and open digital economic systems. Although this is a review of concepts you may already feel familiar with, the history of these systems is quite interesting and worth understanding.

# Revisiting Eth1

Our exploration of Eth2 begins with a foray into some of the fundamental elements of Eth1. The concepts and theories of Eth1 are, after all, the original basis of Eth2. One cannot easily begin understand Eth2 without first embarking on an archeological dig of its ancestral components.

Through the lens of Eth1 we introduce many of the core aspects of modern blockchain protocols. This familiar ground serves as base camp for in-depth study of the models for blocks, transactions, and consensus mechanisms found in almost every blockchain system today. Many of the same fundamentals behind Eth1 can be found playing leading roles in the dance of Eth2.

The elements of Eth1 also serve to reveal the design's inherent limitations. It is, of course, these very limitations that motivate the development of Eth2. Many of the guiding factors behind Eth2 can be best understood as direct responses to flaws in Eth1. We additionally note some of the various alternative approaches to these problems before we finally embark on our journey into Eth2 proper.

# Exploring Eth2

Our mission is prefaced with a high-level and intuitive introduction to the pillars of Eth2. As such, readers can develop a mental model of the system to serve as reference during our deep-dives into its various components. The intricate elements of Eth2 are much more easily understood when contextualized to the the entirety of the system. In Exploring Eth2 we take a high-level look at Eth2, try to understand some historical context behind the project, and explain the constraints within which the project is being developed.

# Proof of Stake in Ethereum

Our first true technical rabbit-hole is that of Eth2's Proof of Stake protocol. Perhaps one of the greatest achievements within Eth2, this protocol represents the cumulative effort of countless individuals over the better part of the last decade. We approach this subject with a theoretical mindset, opting to leave implementation details to later chapters. Our study of Proof of Stake attempts to build an intuitive understanding of each of the system's mechanisms as responses to concrete problems.

# Eth2 Building Blocks

Eth2 Building Blocks takes a look at the core technical components that make Eth2 possible. Proof of Stake in Ethereum introduces many concepts in the abstract, leaving more specific implementations for Eth2 Building Blocks. Here we explain, at a low level, how elements like RANDAO, BLS Signatures, and the Deposit Contract work under the hood.

# Building the Beacon Chain

We expand on the theoretical base of Chapter 3 with a detailed exploration of its implementation, the Eth2 Beacon Chain. In Building the Beacon Chain we uncover how the conceptual operation of Eth2 is put into practice. We'll be using the building blocks described in Eth2 Building Blocks to properly implement the protocol described in Proof of Stake in Ethereum. By the end of this chapter, readers will be able to map the various elements of Eth2's Proof of Stake protocol to corresponding logic within the Beacon Chain.


TODO

There will be more content after this, I just haven't figured out the structure for those chapters yet