Monero relies heavily on a cryptography principle known as *public/private key cryptography* or *asymmetric cryptography*, which is thoroughly detailed in [this Wikipedia article](https://en.wikipedia.org/wiki/Public-key_cryptography).
Over and above backing up your @mnemonic-seed so that you have access to your account in the event of critical data loss, it is also important to practice good security. Use a secure password when creating a local Monero account (not used on [MyMonero](https://mymonero.com) or other web-based account systems).
Providing access to your Monero account to your next of kin is just as easy as it is to backup your Monero account. Simply leave your @mnemonic-seed to them in your will, or store it somewhere safe where it will be given to them upon the execution of your will. A key advantage to this is that your next of kin won't have to wait for months for a third party to release the funds to them.
The private keys for both of these must be protected by you in order to retain your account privacy. On the other hand, the public keys are obviously public (they are part of your Monero account address). For normal public/private key cryptography someone could send you a private message by encrypting it with either of your public keys, and you would then be the only one able to decrypt it with your private keys.
This means that individuals can easily create a Monero account for themselves as well as a joint account to share with their partner, and individual accounts for their children. Similarly, a business could create separate accounts for each division or group. Since Monero's @transaction fees are quite low, moving funds between accounts is not an expensive exercise.
Those familiar with Monero's predecessors will be more familiar with the term *wallet* to describe this. In Monero we call this an account, and it is a private account owned and operated by a Monero user.
When you manage your own Monero Account with the private @spend-key, you are solely responsible for the security of your funds. Thankfully, Monero makes it very easy to backup your account. When creating a Monero account for the first time you will be given a unique @mnemonic-seed for your account that consists of 13 or 25 words in the language of your choosing. **This seed is the only thing you need to backup for your account**, and so it is imperative that it is written down and stored securely.Never store this seed in a form or location that would allow someone else to see it!
Your account contains all of the Monero @transactions you have sent and received. Your account balance is a sum of all the Monero you've received, less the Monero you've sent. When using Monero you may notice that your account has two balances, a locked and an unlocked balance. The unlocked balance contains funds that can be spent immediately, and the locked balance contains funds that you can't spend right now. You may receive a transaction that has an @unlock-time set, or you may have sent some Monero and are waiting for the @change to come back to your wallet, both situations that could lead to those funds being locked for a time.
Your account is based on two keys, a @spend-key and a @view-key. The @spend-key is special in that it is the single key required to spend your Monero funds, whereas the @view-key allows you to reveal your @transactions to a third party, for example for auditing or accounting purposes. These keys in your account also play an important role in Monero's @transaction's privacy.
