Oh boy, Jackie! Whew! Where to start.
To make it easy just think of justify/justification as newspaper jargon.
The columns of type set on a linotype were put into page-size cases and the page was laid out in those cases with headlines, photos (steel engravings)included by a make-up man (all men in my day.) As a beginning reporter I sometimes checked the Women's Pages as they were being made up. If there was a story in type that didn't fit the page the story was cut by removing the type from the bottom of the story. Hence the typical pyramid style of news writing :the most important information in first graph, exposition following in order of precedence. After the page was made up the form was locked and sent off to the printers.
Sometimes if a line was a tiny bit short - to make it all nice and justified - or to avoid a ridiculous hypenation - a slim piece of metal was placed to space out the words. These small pieces of metal are called (letter) spacers.
It was fine to letterspace regular type but a big no-no for italic letter. Hence the sign seen in many old makeup areas :
"He who would letterspace italics would steal sheep."
Hi CapK!
Oh, and just to keep it interesting for whomever was checking the pages, the page faced the make-up man so the reporter/editor had to "read" the page upside down and backwards!
This skill has come in very handy now and then!
I went to an ATEX school when we first went to computers in newspapers and about two days in to the course I was ready to cry with frustration but was saved by two Scots who were there to learn the whole system ... when they learned that I had worked in hot type they explained a computer builds bfrom the bottom up just like when the lead was pouring into letter forms.
Now, is that more than you needed to know?
Aloha!