diff --git a/04_1_Sending_Coins_The_Easy_Way.md b/04_1_Sending_Coins_The_Easy_Way.md
index cdfbb7f..325195d 100644
--- a/04_1_Sending_Coins_The_Easy_Way.md
+++ b/04_1_Sending_Coins_The_Easy_Way.md
@@ -3,6 +3,32 @@ TODO:
 * Also: Fees. There was some question of if mintxfee is still current, or if paytxfee should be used. I haven't seen any evidence of obsolence, but it'd be good to check this and make sure we're still on the best practices.
 * Also: sendall as an alternative
 
+==
+UNDERSTANDING ADDRESSES MIGHT BE A WHOLE NEW SECTION
+==
+### Knowing Your Bitcoin Addresses
+
+There are three types of Bitcoin addresses that you can create with the `getnewaddress` RPC command. You'll be using a `legacy` (P2PKH) address here, while you'll move over to a SegWit (P2SH-SegWit) or Bech32 address in [§4.6: Creating a Segwit Transaction](04_6_Creating_a_Segwit_Transaction.md).
+
+As noted above, the foundation of a Bitcoin address is a public key: someone sends funds to your public key, and then you use your private key to redeem it. Easy? Except putting your public key out there isn't entirely secure. At the moment, if someone has your public key, then they can't retrieve your private key (and thus your funds); that's the basis of cryptography, which uses a trap-door function to ensure that you can only go from private to public key, and not vice-versa. But the problem is that we don't know what the future might bring. Except we do know that cryptography systems eventually get broken by the relentless advance of technology, so it's better not to put raw public keys on the 'net, to future-proof your transactions.
+
+Classic Bitcoin transactions created P2PKH addresses that added an additional cryptographic step to protect public keys.
+
+> :book: ***What is a Legacy (P2PKH) address?*** This is a Legacy address of the sort used by the early Bitcoin network. We'll be using it in examples for the next few sections. It's called a Pay to PubKey Hash (or P2PKH) address because the address is a 160-bit hash of a public key. Using a hash of your public key as your address creates a two-step process where to spend funds you need to reveal both the private key and the public key, and it increases future security accordingly. This sort of address remains important for receiving funds from people with out-of-date wallet software.
+
+As described more fully in [§4.6: Creating a Segwit Transaction](04_6_Creating_a_Segwit_Transaction.md), the Block Size Wars of the late '10s resulted in a new sort of address: SegWit. This is the preferred sort of address currently, and should be fully integrated into Bitcoin-Core at this point, but nonetheless we're saving it for §4.6.
+
+SegWit simply means "segregated witness" and it's a way of separating the transaction signatures out from the rest of the transaction to reduce transaction size. Some SegWit addresses will sneak into some of our examples prior to §4.6 as change addresses, which you'll see as addresses that begin with "tb". This is fine because the `bitcoin-cli` entirely supports their usage. But we won't use them otherwise.
+
+There are two addresses of this sort:
+
+> :book: ***What is a P2SH-SegWit (aka Nested SegWit) address?*** This is the first generation of SegWit. It wraps the SegWit address in a Script hash to ensure backward compatibility. The result creates transactions that are about 25%+ smaller (with corresponding reductions in transaction fees). 
+
+> :book: ***What is a Bech32 (aka Native SegWit, aka P2WPKH) address?*** This is the second generation of SegWit. It's fully described in [BIP 173](https://en.bitcoin.it/wiki/BIP_0173). It creates transactions that are even smaller but more notably also has some advantages in creating addresses that are less prone to human error and have some implicit error-correction beyond that. It is *not* backward compatible like P2SH-SegWit was, and so some people may not be able to send to it.
+
+There are other sorts of Bitcoin addresses, such as P2PK (which paid to a bare public key, and is deprecated because of its future insecurity) and P2SH (which pays to a Script Hash, and which is used by the first-generation Nested SegWit addresses; we'll meet it more fully in a few chapters).
+==
+
 # 4.1: Sending Coins the Easy Way
 
 The `bitcoin-cli` offers three major ways to send coins: as a simple command; as a raw transaction; and as a raw transaction with calculation. Each has their own advantages and disadvantages. This first method for sending coins is also the simplest.