https://bitcoinarmory.com/tutorials/armory-advanced-features/offline-wallets/
The concept is to have your normal computer online with a "watching only" copy of the wallet. This copy doesn't have any private keys, it only knows the bitcoin addresses.
Since it knows all the bitcoin addresses that you control, it is able to update your balances from the blockchain and let you know when you've received transactions. Since it doesn't have any private keys, malware and hackers won't be able to gain access to your bitcoins from this computer.
Then you have a second computer that is never connected online. This computer stores your private keys. Since it has the private keys, it can sign transactions. It doesn't have access to the blockchain, so it doesn't know what your balances are.
You can create an unsigned transaction with the online computer. Then save that transaction to media that can be carried to the offline computer (such as USB, or SD card). Then you can use the offline computer to sign the transaction, and save the signed transaction to media that can be carried mack to the online computer. Then broadcast the transaction from the online computer.
https://bitcoinarmory.com/tutorials/armory-advanced-features/offline-wallets/
Yes.