🚀 go-pugleaf

Just wanted to correct Charles Hedrick's statement. There are 3 accepted solutions: 

1. en dash surrounded by spaces of the line. 

2. em dash flush 

3. em dash surrounded by thin or hair spaces. 

# 1 is the practice introduced by Tschichold  at Penguin in 1947-8 and is widely seen today; #2 is an English practice; #3 is originally a Continental practice but is now also widely seen everywhere. If you use em dashes, whether you do 2 & 3 depends on the actual font, as some designers build the hair-spacing into the glyph. 

Bringhurst considers em dashes to be relics of the 'padded and corseted Victorian typographic aesthetic' or some such nonsense, but this is historically utterly incorrect: em dashes certainly occur in C18th typography, and they appear to me to have been used by Gutenberg in the 43-line Bible.