Chorded keyboard (a writing system for the blind) uses either 6 or 8 tactile 'points' from which all letters and numbers are formed. When Louis Braille invented it, it was produced with a needle holing successively all needed points in a cardboard sheet. In 1892, Frank Haven Hall, superintendent of the Illinois Institute for the Education of the Blind, created the Hall Braille Writer, which was like a typewriter with 6 keys, one for each dot in a braille cell. The Perkins Brailler, first manufactured in 1951, uses a 6-key chord keyboard (plus a spacebar) to produce braille output, and has been
How to Read a Book makes a brief argument favoring the Great Books, and explains his reasons for writing "How to Read a Book". There are three types of knowledge: practical, informational, and comprehensive. He discusses the methods of acquiring knowledge, concluding that practical knowledge, though teachable, cannot be truly mastered without experience; that only informational knowledge can be gained by one whose understanding equals the author's; that comprehension (insight) is best learned from who first achieved said understanding — an "original communication". The idea that communication directly from those who first discovered an idea is the best way of gaining understanding is Adler's argument