If the Public-folder method seems too simple and restrictive, then you can graduate to the “share any folder” method. In this scheme, you can make any file, folder, or disk available to other people on the network.
The advantage here is that you don’t have to move your files into the Public folder; they can sit right where you have them. And this time, you can set up elaborate sharing privileges (also known as permissions) that grant individuals different amounts of access to your files.
This method is more complicated to set up than that Public-folder business. In fact, just to underline its complexity, Apple has created two different setup procedures. You can share one icon at a time by opening its Get Info window; or you can work in a master list of shared items in System Preferences.
The following pages cover both methods.
Here’s how to share a Mac file, disk, or folder disk using its Get Info window.
The following steps assume that you’ve turned on 
→System Preferences→Sharing→File Sharing, as shown in Figure 14-5.
Highlight the folder or disk you want to share. Choose File→Get Info.
The Get Info dialog box appears (Figure 14-6). Expand the General panel, if it’s not already visible.
Figure 14-6. The file-sharing permissions controls are here, in the Get Info box for any file, folder, or disk.
Note
Sharing an entire disk means that every folder and file on it is available to anyone you give access to. On the other hand, by sharing only a folder or two, you can keep most of the stuff on your hard drive private, out of view of curious network comrades. Sharing only a folder or two does them a favor, too, by making it easier for them to find the files they’re supposed to have. This way, they don’t have to root through your entire drive looking for the folder they actually need.
Turn on “Shared folder.”
Enter your administrator password, if necessary.
Tip
To help you remember what you’ve made available to other people on the network, a banner labeled “Shared Folder” appears across the top of any Finder window you’ve shared. It even appears at the top of the Open and Save dialog boxes.
OK, this disk or folder is now shared. But with whom?
Expand the Sharing & Permissions panel, if it’s not already visible. Click the
icon and enter your administrator’s password.The controls in the Sharing & Permissions area spring to life and become editable. At the bottom of the Info panel is a little table. The first column can display the names of individual account holders, like Casey or Chris, or groups of account holders, like Everyone or Accounting Dept.
The second column lists the privileges each person or group has for this folder.
Now, the average person has no clue what “privileges” means, and this is why things get a little hairy when you’re setting up folder-by-folder permissions. But read on; it’s not as bad as it seems.
Edit the table by adding people’s names. Then set their access permissions.
At the moment, your name appears in the Name column, and it probably says Read & Write in the Privilege column. In other words, you’re currently the master of this folder. You can put things in, and you can take things out.
If you just want to share files with yourself, so you can transfer them from one computer to another, you can stop here.
If you want to share files with other people—well, at the moment, the privileges for Everyone are probably set to “Read only.” Other people can see this folder, but they can’t do anything with it.
Your job is to work through this list of people, specifying how much control each person has over the file or folder you’re sharing.
To add the name of a person or group, click the + button below the list. The list shown in Figure 14-7 appears.
Now click a name in the list. Then, from the Privilege pop-up menu, choose a permissions setting.
Read & Write has the most access of all. This person, like you, can add, change, or delete any file in the shared folder, or make any changes she likes to a document. Give Read & Write permission to people you trust not to mess things up.
Read only means “Look, but don’t touch.” This person can see what’s in the folder (or file) and can copy it, but he can’t delete or change the original. It’s a good setting for distributing company documents or making source files available to your minions.
Write only (Drop Box) means that other people can’t even open the folder. They can drop things into it, but it’s like a mail slot: The letter disappears into the slot, and then it’s too late for them to change their minds. As the folder’s owner, you can do what you like with the deposited goodies. This drop-box effect is great when you want students, coworkers, or family members to be able to turn things in to you—homework, reports, scandalous diaries—without running the risk that someone else might see those files. (This option doesn’t appear for documents—only disks and folders.)
No access is an option only for Everyone. It means that other people can see this file or folder’s icon but can’t do a thing with it.
Close the Get Info window.
Now the folder is ready for invasion from across the network.
It’s very convenient to turn on sharing one folder at a time, using the Get Info window. But there’s another way in, too, one that displays all your shared stuff in a handy master list.
To see it, choose →System Preferences. Click Sharing. Click File Sharing (and make sure it’s turned on).
Now you’re looking at a slightly different kind of permissions table, shown in Figure 14-8. It has three columns:
Shared folders. The first column lists the files, folders, and disks you’ve shared. You’ll probably see that every account’s Public folder is already listed here, since they’re all shared automatically. (You can turn off sharing for a Public folder, too, just by clicking it and then clicking the — button.)
But you can add more icons to this list. Either drag them into the list directly from the desktop or a Finder window, or click the + sign, navigate to the item you want to share, select it, and then click Add. Either way, that item now appears in the Shared Folders list.
Users. When you click a shared item, the second column sprouts a list of who gets to work with it from across the network. You’re listed here, of course, since it’s your stuff. There’s also a listing here for Everyone, which really means “everyone else”—that is, everyone who’s not specifically listed here.
Figure 14-8. Hiding in System Preferences is a list of every disk and folder you’ve shared. To stop sharing something, click it and then click the — button. To share a new disk or folder, drag its icon off the desktop, or out of its window, directly into the Shared Folders list.
You can add to this list, too. Click + to open the person-selection box shown in Figure 14-7. It lists the other account holders on your Mac, and some predefined groups, as well as the contents of your Contacts.
Note
Most of the Contacts people don’t actually have accounts on this Mac, of course. If you choose somebody from this list, you’re asked to make up an account password. When you click Create Account, you’ve actually created a Sharing Only account on your Mac for that person, as described in the box below. When you return to the Accounts pane of System Preferences, you’ll see that new person listed.
Double-click a person’s name to add her to the list of people who can access this item from over the network, and then set up the appropriate privileges (described next).
To remove someone from this list, just click the name and then click the — button.
Users. This third column lets you specify how much access each person in the second column has to this folder. Your choices, once again, are Read & Write (full access to change or delete this item’s contents); Read Only (open or copy, but can’t edit or delete); and Write Only (Drop Box), which lets the person put things into this disk or folder, but not open it or see what else is in it.
For the Everyone group, you also get an option called No Access, which means that this item is completely off-limits to everyone else on the network.
And now, having slogged through all these options and permutations, your Mac is ready for invasion from across the network.