Open the panel from the window menu (Window -> Align) and make sure the whole panel is visible by clicking either on the little arrows to the left of the word ALIGN or by using the flyout menu option “Show Options” (shown as “Hide Options” in the screenshot since it’s already visible)

So now you see that it’s actually 2 tools tucked in one interface – Align and Distribute.

Starting with the basic Align:

You can either align based on your objects or based on the artboard.  You choose that using the “Align To:” button in the lower right of the panel.

(To start with, be sure that the “Align To:” button is set to “Align to Selection”)

The “Align to Selection” behavior of Align (the default behavior) is pretty straightforward.  Each of the buttons will align either to an edge (left, right, top or bottom) or the center (vertical or horizontal)

Here’s a few objects to demonstrate Align to Selection with -

And here are those objects aligned using each of the 6 align buttons.

By default, the objects will align relative to the bounding box of all the selected objects – in practical terms, that means that if you’re aligning to the left, the leftmost object will stay put and all the others will shift over to that object and if you’re center-aligning, it will align to the average center point.

You can also align to a specific object.

You can fix the position of one of your objects and align the rest of the selected objects in relation to it.  Do this by defining that object as the Key Object.  To do so, you select all the objects you want to align and then just click again on the object you want to be the key object.  (Regular click, not shift click – That’ll just deselect it.)

The method has been the same for as far back as I know, but as of CS4, there is actually a way to tell which object you’ve selected – it gets a bolder selection line around it and the “Align To:” button changes to “Align to Key Object”  This still works in previous versions but there is no visual feedback for the key object.

Align works the same with a key object defined as without, it just keeps the key object locked in place and moves all the others in relation to the key object instead of moving all the objects.

You can also align to the artboard.

Aligning to the artboard is essentially calling the artboard your key object and will move everything based on the boundaries of the artboard.

(It’s hard to see in my cropped screenshot, but those objects are actually aligned to the artboard)

You can also align points to points

To do so, use the direct select tool (the white or hollow arrow) and the last point you select will be considered the key object (though there is no visual feedback)

“Use Preview Bounds”

Way up there in the first screenshot, you see the option to “Use Preview Bounds”.  This will consider the stroke width instead of the center of the stroke itself as the edge of the alignment.

Here’s an example of aligning an object with a 10 point stroke.

Use Preview Bounds will also change the information that you get from the Transform Panel to consider the added dimensions of the stroke (or the added or subtracted dimensions of any effects)

I’ll get to the distribute section of the panel in a later post – it’s past my bedtime.