# Jeffrey Friedl Jeffrey E. F. Friedl is an American software engineer best known as the author of *Mastering Regular Expressions* (O'Reilly), the definitive book on the subject and the reference most working programmers reach for when learning how regex engines actually behave. First published in 1997 and now in its third edition, the book is notable for explaining not just syntax but the mechanics of how different engines (NFA vs DFA, backtracking vs automata) match text, and why the same pattern can behave differently across flavors. Friedl has worked at companies including Omron in Japan and Yahoo!, and runs the site regex.info, where he also publishes on photography and digital image metadata. ## Related - [[Regular Expressions (Regex)]] ## Quotes <!-- QueryToSerialize: LIST FROM #type/quote AND [[Jeffrey Friedl]] WHERE public_note = true SORT file.name ASC --> ## Books <!-- QueryToSerialize: LIST FROM #books AND [[Jeffrey Friedl]] WHERE public_note = true SORT file.name ASC -->