This is one of the nice article in usability. In GUI, a dialog box is a special window , which is used in user interface to present information to the users. Basically, dialog boxes are classified as model or modeless.
The author has mentioned some basics of dialog usability with the number of screenshots by comparing some correct or incorrect application design.
The author has given some basic guide lines that is required while using dialog box. The author has explained how to choose right dialogs at the right places and how to choose the right layout and fonts for displaying the content in the dialog.
This article provides an excellent knowledge of dialog box usability for beginners.
A comprehensiv article on the usability of using Dialog boxes in mobile applications.
The article is recommended to beginners to keep in mind certain basic usability aspects for using Dialog boxes. The article compares the ideal design with the poor design with help of the images. The distinction made using the images/examples make it easy to understand the Dialog usability.