Many attempts made by eminent scholars to decode the Indus script did not yield desired result. This does not imply that the efforts were useless. Some of them did provide a clue to a few knotty problems. The historians, archaeologists and epigraphists in general have however been saying that the script is undecipherable. This is because the script is so complicated that few would like to study carefully the various attempts made in the past and to assess their usefulness. But none can deny the importance of deciphering the Indus script. Fortunately the attempt made by an excavator of Indus sites has resulted in a breakthrough as a sequel to scientific analysis and careful comparison with a known script All the ramifications of analysis and interpretation by various scholars are not brought together in a single monograph and examined objectively to enable the interested scholars to pass an unbiased judgement. The present work on structural analysis not only meets this desideratum but also throws new light on the different approaches to the problems, some based on a priori assumptions. It has convincingly demonstrated that the failure by most scholars to carry the structural analysis of all compound signs in Indus script to its logical conclusion and a-priori assumptions of a language of their choice were the stumbling blocks which only one decipherer has removed and obtained satisfactory results. The stages by which the basic signs were identified and compared with those of a known script resulting in identifying the language as old Indo-Aryan are explained vividly with adequate analytical charts and examples. It makes a clear presentation of the problems and various attempts made by scholars to decipher the script The author has cleared the mystery of the so-called undecipherable script and highlighted the fact that objectivity and intuition have solved the problem. The scholar will now be able to further interprete the readings of the enciphered script and suggest alternate meanings of phonemes if any. The author has rendered signal service to the scholarly world by providing basic data needed for understanding the intricacies of a mixed writing of bygone days.