You can quickly get help with the buttons and menu commands you see on the interface in ArcReader. Hover over a command or button with the mouse pointer and press Shift+F1 on your keyboard.
You can also get help on some dialog boxes. When you click the What's This? button 
in the upper right corner of the dialog box and click an item on that dialog box, a description of the item pops up.
You can look up general help topics in the installed help system using the Contents tab. The Index tab allows you to search for specific tasks and issues within the help. You can also use the Search tab to search for specific words or phrases in a help topic. For the latest ArcReader help, click ArcReader Web Help from the Help menu.