Google has now made its Drive service more than an online storage product and productivity suite. You can now edit documents you have stored on Google Drive (or Docs, if you haven't moved over to the new interface) during those moments -- while sitting on an airplane or in a cabin in the woods or in a Wi-Fi-free coffee shop -- when you are not connected to the Internet. And when you open that same document when you are back online, the changes you made while offline are there. (For some reason, Google is putting this offline access under the old Docs banner.) Here's how to start using Google Docs offline.
To begin, Google Docs offline is available only in Google's own Chrome browser. To enable offline access, go to your Google Drive page and click the gear icon in the upper-right corner and select Set up Google Docs offline. A window will pop up with a two-step setup process. Click the Enable offline Docs button and then for Step 2, you will need to install the Drive Web app for Chrome. Click the second blue button in the window and you will be taken to the Chrome Web store to install the Drive Web app.
After installing the Web app, return to your Drive home page and you'll see a notification pointing to the gear icon that informs you that some of your recent files are being synced and how to view them. To see which docs are available offline, click the gear icon and choose "view offline Docs." It opens a new Google Docs offline tab in Chrome. Bookmark this page so you can access it in Chrome when you are without the Internet.
Google Docs offline shows you only Documents and Spreadsheets; Presentations, Drawings, and Forms don't make the jump. And you can edit Documents but can only view Spreadsheets. And despite there being a grayed-out red (pinked out?) New Document button, you cannot create new documents in offline mode. Given the presence of such a button, I'd wager that this feature is coming soon.
I hope support for multiple accounts is coming soon, too. I have two Google accounts, and when I logged out of the first account with which I had set up Google Docs offline and logged in to my second account in Chrome, I was unable to get it working. I went through the same process, but it told me that both steps of enabling offline Docs and installed the Chrome Web app were complete, but it didn't give me the link to open Docs offline. So, I am currently stuck using Google Docs offline with only one account, but I suspect this is a bug Google will soon work out.