Plain English
An order book is the list of buy orders (bids) and sell orders (asks) at different prices for a given trading pair. The exchange matches a buyer’s bid with a seller’s ask at the agreed price. Order books are the traditional way centralized exchanges match trades; DEXes use AMMs instead.
How it actually works
On the bid side, buyers post the price they are willing to pay and the size they want. On the ask side, sellers post their offering price and size. The highest bid and lowest ask form the “best bid” and “best ask;” the gap between them is the spread. When a market order arrives, it walks down (or up) the book consuming liquidity until filled.
What it means for you
For members trading on a CEX (Coinbase, Kraken, Binance), the order book is the venue. The depth at each price level tells you what size you can move without significant slippage. For passive holders, the order book is a tool, not a daily concern.
We teach order-book reading for execution discipline: how to evaluate true liquidity, when to use limit orders versus market orders, and how to split large trades to avoid moving the book.
Educational content only. Not investment, tax, or legal advice.