The term hypertext refers to the ability to go from one page (or screen) to another at the click of a mouse. This manual was prepared by inserting extra information inside the same characters used to indicate greater or lesser in math. This is called HTML--hypertext markup language. (Some browsers will allow you to view the document file so that you can see what these characters look like.)
You might note that all the distinct files that make up this manual
are referred to as SLIPS, an acronym for Symbolic Logic Independent Page
Set. Each page has colored words or phrases that, when clicked on, take
you to a different page. You can always return to where you were by clicking
on the left-hand marker in your tool bar. If you want a full screen without
any icons there usually is a way of doing this (sometimes it is called
"presentation mode") and you can return the tool bars by using your ESC
key.
Go on to About Postfix Literal Notation.
Go back to the starting page.