From Descartes to punk rock, X has an extraordinary history

The letter X can be a lot of things: rebellious, mysterious, religious. For this Word of the Week, we examine its origins and ...
Smithsonian Magazine

A Brief History of the Letter ‘X,’ From Algebra to X-Mas to Elon Musk

The letter “x” often symbolizes something unknown, with an air of mystery that can be appealing. Illustration by Meilan Solly Even though “x” is one of the least-used letters in the English alphabet, ...
insider.si.edu

The Edinburgh companion to nineteenth-century American letters and letter-writing / edited by Celeste-Marie Bernier, Judie Newman, and Matthew Pethers

Series from publisher's Web site. NPM copy purchased with Adopt-a-Book funds. Contents Prologue : networks of nineteenth-century letter-writing / Elizabeth Hewitt -- Introduction : epistolary studies ...