Of the writing systems of the ancient world which still await deciphering, the Indus script is the most important. It developed in the Indus or Harappan Civilization, which flourished c. 2500–1900 BC in and around modern Pakistan, collapsing before the earliest historical records of South Asia were composed. Nearly 4,000 samples of the writing survive, mainly on stamp seals and amulets, but no translations. Professor Parpola is the chief editor of the Corpus of Indus Seals and Inscriptions. His ideas about the script, the linguistic affinity of the Harappan language, and the nature of the Indus religion are informed by a remarkable command of Aryan, Dravidian, and Mesopotamian sources, archaeological materials, and linguistic methodology. His fascinating study confirms that the Indus script was logo-syllabic, and that the Indus language belonged to the Dravidian family.