Slides, Masters, Designs, Layouts ... how do they all fit together?
Moving from earlier versions of PowerPoint to 2002/2003 and then to 2007 can be confusing, especially when it comes to slide masters.
This will help you understand how they work in the various versions of PowerPoint.
PowerPoint 2000 and previous
In PowerPoint 2000 and earlier, each presentation has a single Slide Master and optionally a Title Master.
Each slide has one of several available AutoLayouts (Title, Title Only, Title + Text and so on). You can choose the AutoLayout you want when you insert a new slide or you can apply a different AutoLayout to a slide at any time later.
You cannot edit AutoLayouts.
If the presentation contains a Title Master, PowerPoint uses it to format slides with the Title AutoLayout. All other AutoLayouts are formatted according to the Slide Master.
If the presentation doesn't include a Title Master, PowerPoint formats Title slides according to its internal defaults. These are the same defaults it uses when you add a new Title Master (by choosing Insert, New Title Master while in Slide Master view).
PowerPoint 2002 and 2003
PowerPoint 2002 introduced Multiple Masters.
In PowerPoint 2002/2003, each presentation can have many Slide Masters. Each Slide Master can optionally have a linked Title Master.
The rules for AutoLayouts and Title Masters are the same as in previous versions, but since you can have multiple Slide (and Title) Masters, you can approximate the effect of having customized AutoLayouts.
Sometimes you'll hear the term "Designs" used in reference to PowerPoint 2002/2003 and its masters. Internally, it considers each Slide Master (and its optional Title Master, if any) a Design. This is mostly of interest to programmers. Ordinary Humans don't need to worry about it.
PowerPoint 2007 introduced customizable AutoLayouts.
Now each presentation can have multiple Slide Masters. Each Slide Master is actually a collection of Custom Layouts. You can edit the existing Custom Layouts or add new ones as needed.
Where before each Slide Master could have a linked Title Master, the Title Master now is one of the Custom Layouts.
Here's how the different versions look in a kind of "outline" form:
PowerPoint 2000 and previous:
Slide Master AutoLayouts (uneditable) Title Master (optional)
Slide Master AutoLayouts (uneditable) Title Master (optional) Slide Master2 AutoLayouts (uneditable) Title Master2 (optional) Slide Master3 AutoLayouts (uneditable) Title Master3 (optional) .... and so on
PowerPoint 2007 (and presumably later):
Slide Master Title Slide Layout (editable) Title and Content Layout (editable) ... Total of 11 editable Layouts plus ... Custom Layouts you add Slide Master2 Title Slide Layout (editable) Title and Content Layout (editable) ... Total of 11 editable Layouts plus ... Custom Layouts you add Slide Master3 Title Slide Layout (editable) Title and Content Layout (editable) ... Total of 11 editable Layouts plus ... Custom Layouts you add ... and so on