typography

 Typography  is the art/science of making text attractive and readable.

Among the most important considerations is the idea of managing the length of a line, in terms of the number of characters. A line of between 45 and 90 characters is widely considered more readable than both longer and shorter lines. The lines in this paragraph are not very readable on a desktop computer screen without adjusting the size of the typeface.

Additional considerations for typesetting include:
 * Leading a.k.a. `line-height`, the space between lines of text
 * Kerning a.k.a. `letter-spacing`, the space between individual characters

Buttericks Practical Typography is a very good introduction to almost all aspects of typography for online and print.

Vertical Rhythm

 * http://vertical-rhythm.crasman.fi/
 * http://vertical-rhythm.crasman.fi/