Daniels (born December 11, 1951) is a scholar of writing systems, specializing in typology.
He was co-editor (with William Bright) of the book The World's Writing Systems (1996), and he introduced the terms abjad (an "alphabet" with no vowel letters) and abugida (a system partly alphabetic, partly syllabic) as modern linguistic terms for categories of scripts.
(These terms had been used previously in a more restricted sense by specialists in the fields of the Arabic alphabet and Ge'ez script, from which languages they were borrowed respectively.)
Daniels is interested in cryptic crosswords and has often posted to the rec.puzzles.crosswords newsgroup.