In one form or another, the so-called Linear script of Class A was used in parts of Minoan Crete from the 20th to the middle of the 15th century B.C. It is closely related to two other Cretan scripts, with both of which it overlaps to some extent: an earlier (known as Hieroglyphic or, better, as Pictographic) and a later (known as the Linear script of class B). The precise nature of the interrelationship of these three scripts is not clear. They do not, apparently, descend from one another by a simple process of development. Rather, both Linear A and Linear B seem to have selected elements from a common source, which is either the Pictographic script itself or a system of writing allied to it. The closest similarity between the two classes of Linear script is evident in their external character, that is to say, in the shapes of individual signs: even so, only about half of the signs in the Linear A system have the same shape as those in Linear B. There is much less resemblance in internal character (the structure and function of the scripts). For example, although we find in Linear A many single signs (apparently ideographic or determinative in function) and also sign-groups (which, by reason of the small number employed in all and also by analogy with Linear B practice, are almost certainly phonetic), ideograms are very rarely juxtaposed with phonetic groups, as constantly happens in Linear B. Linear A offers only two certain examples of such juxtaposition, namely in HT 15:1 and 88:4, and even there the order is the reverse of that in Linear B, where the phonetic group regularly precedes the ideogram.

As late as 1920 it was believed that civilization on the Indian subcontinent dated back only to the time of Alexander's invasion in the 4th century b.c. and that everything before that was “dark”. This assumption was made in spite of the fact that literary evidence pointed to the contrary. However, in 1921 the “belief” received its first blow when Daya Ram Sahni discovered the site of Harappa; the second one came just a year later when R. D. Banerji discovered Mohenjo-daro. Subsequent excavations at these two sites and at another site called Chanhu-daro, respectively by M. S. Vats, John Marshall, and E. J. H. Mackay, brought to light fuller details of the civilization which encompassed the Indus valley in the 3rd millennium b.c. The more recent work at Amri, Damb Sadaat, Gumla, Jalilpur, Kalibangan, Kot Diji, Lothal, Sarai Khola, and Surkotda has added new dimensions to our knowledge of this civilization.

The Indus script is at present known from about 3,000 inscriptions with an average length of only five signs. The longest continuous text (1400) comprises only 17 characters divided over three lines. There are no bilingual inscriptions. Also, direct historical data relating to the Indus civilization are extremely scanty, being limited to the scarce references in cuneiform texts of the 3rd and early 2nd millennia B.C. to trade and other contacts with Meluḫḫha, the most distant country known to the Mesopotamians of those times, whose identity with the Indus civilization at the period in question is now widely accepted. More texts in the Indus script are, and will be, forthcoming from recent and imminent excavations, and perhaps the excavations that are under way in ancient Lagaš will bring to light the long-expected bilingual, possibly in the form of a cuneiform document mentioning Meluḫḫan proper names and bearing the impression of an Indus seal. In the absence of such a clue, the prospects of ever understanding the Indus script have generally been considered rather meagre. This pessimistic attitude has long been obstructing progress in the study of the Indus script. The very first point I should like to make is, that despite the scantiness of the material, it is indeed possible to promote our knowledge in many ways, and that important results are sure to come from more work by more people. One of our greatest needs at the moment is an increase of interest in the Indus script, and the coordination of scholarly efforts.