This, the second volume of a comprehensive catalog of Indus signs "lists all Indus inscriptions that are currently available and presents the temporal as well as spatial distribution of inscribed artefacts," writes the author, Dr. Fuls, who developed the extraordinary database that is the book's backbone (Vol. I is discussed at Corpus of Indus Inscriptions [I]). He also has run the various statistical analyses and comparisons performed to better understand the ancient Indus sign system. In this effort he has worked closely with Dr. Bryan Wells, whose Ph.D at Harvard on the Indus script followed an almost 30 year fascination with the subject. Dr. Wells started in his Master thesis in 1999, building up his sign list without reference to Mahadevan or Parpola's earlier ones for which a concordance was added later as a quick reference for scholars still using those sign lists. This sign list has more signs, some 700 vs. the roughly 400 of earlier efforts. While this may be a matter of discussion (see Parpola's response Signs of the Indus Script and their Variants), what is clear is that the comprehensiveness (over 5,000 inscriptions) and ease of use and care with which each inscription has been added – inclusive of known about location, date, type of material etc. – comprises an enormous foundational contribution to the study of this ancient communication system.

Since the Indus script remains undeciphered, the catalog does not provide major new breakthroughs in understanding the language or content of the inscriptions. Nonetheless, it serves as a crucial tool for researchers attempting to decode the Indus script and understand its context within the Indus Valley Civilization. The volume is organized in a detailed, systematic manner, with extensive visual documentation of the signs, a variety of statistical tables on frequency and distribution of the signs, correlations with other sign listings, frequency of text lengths, terminal markers and much more in addition to its primary function: the detailed rendition of every single sign, where it occurs and in what position (including variants). While the vast majority of known distinct signs are from Mohenjo-daro (541) and Harappa (431), followed by Kalibangan (161), Dholavira (158) and Lothal (152) at latest reading, the book also includes such statistical points like the fact that shortest average text length (3.1) is from Harappa, and longest from Chanhu-daro (4.9) and Mohenjo-daro (4.5). All of this might be the result of the number and nature of excavations at the sites of course, with Harappa and Mohenjo-daro having been excavated the most, but it is this kind of work which helps underlie future analyses and attempts at decipherment.

Dr. Fuls, who is at the Technische Universität Berlin, has worked with other ancient scripts and calendars (his papers at Academia.edu); he has wide experience with comparative data analysis. He has been able to compare the Indus sign lists with other ones and conclude, for example, "that the Indus writing system is a logographic-syllabic writing system with a high number of logograms in the sign list. These logograms, however, are mostly rare, since they represent only a small fraction of all sign occurrences in the entire corpus. The exact degree of phonetization may vary depending on the artefacts and the context" (p. 113). In other words, some signs (logographic) represent entire words, while others are syllabic parts of words. From his analysis of the signs and their positions, Fuls also believes that Indus inscriptions typically represent a single language even if in some areas and contexts other languages might be involved. By cataloging the signs in detail, Fuls' work allows for comparisons with other undeciphered scripts, such as Linear A, or partially deciphered ones, like Linear B and the Egyptian hieroglyphs. This comparative approach can sometimes yield new insights based on parallels in usage or structure.

Andreas Fuls' A Catalog of Indus Signs is a significant academic contribution that offers a detailed and organized reference for the signs of the Indus script, and is paired with the similarly hefty Corpus of Indus Inscriptions. Both provide a solid foundation for future research and have been well-received for their meticulousness and utility. A Catalog of Indus Signs is not just a catalog but a pivotal tool that supports ongoing research, fosters scholarly collaboration, and serves as an educational resource – and, one hopes, inspiration – for further work and scholarship.

Significantly, it is always being added to, and available to interested, qualified scholars and researchers online, although a good place to start would be this and the partner volume, both of which are also available as Kindle editions. There is also a comprehensive one hour presentation on YouTube, by Andreas Fuls, Mathematical epigraphy and the Interactive Corpus of Indus Texts.