Zoe Penn is a student, reader, writer, coder, gamer and logic puzzles solver. She loves solving all kinds riddles, puzzles and cryptographic codes, and writing about them for children. She also loves building worlds, in her imagination and virtual ones. She probably spends too much time on her gaming computer, building and navigating her own worlds, writing fantasy stories and programming codes. Zoe lives in Zagreb, Croatia (Europe).

Zeljko Pahek (Illustrator) is an internationally published illustrator, comic-books and graphic novels creator, cartoonist, and caricaturist. Since 1980s he is known for comic series, as well as cover illustrations for masterpieces of science fiction and fantasy literature. From 1982, Pahek works for many publishing houses as a front page illustrator for science fiction and fantasy books from the writers such as Robert Heinlein, Philip K. Dick, Arthur C. Clarke, Douglas Adams, Terry Pratchett and Tim Powers. Zeljko lives in Belgrade, Serbia (Europe).