The book specimens are unusually interesting. The best specimen, the Dresden Codex, is a screen-fold manuscript about 20 centimeters high and several meters long painted on lime-sized bark paper or clothe. According to J.E.S Thompson, the Maya hieroglyphics combine simple phonetic and ideographic principles.
There was no alphabet, and no fully adequate key for their translation, which explains why only about 25 percent of them have been translated. The Maya hieroglyphics themselves are fantastically grotesque human, monster or deity head forms for the most part. In context, affixes were appended to principal glyphic elements. In Thompson’s opinion, Maya hieroglyphics treated wholly of time, astronomy, astrology, gods and ceremonies. Proskouriakoff, on the other hand, feels that some texts dealt with more mundane matters of dynastic succession and other specific human historical events.