Wolfgang Hadamitzky is a freelance author of Japanese language learning materials and has worked as a librarian on the staff of the East Asia Department of the Berlin State Library and of the German Cultural Institute (Goethe Institute) in Tokyo. Mark Spahn has a background in mathematics, engineering, and computer science and has worked in Japan as a teacher, computer magazine writer, programmer, and translator. He is currently a technical translator and consultant. Hadamitzky and Spahn are the authors of numerous language learning and reference books including The Learner's Japanese Kanji Dictionary, The Kanji Dictionary and A Guide to Writing Kanji & Kana Books 1 and 2. All of which are available from Tuttle Publishing.