The list of katēgoriai presented at the start of Top. I 9 was traditionally interpreted as a version of the canonical Aristotelian list of categories, and as largely equivalent to the list we find in Categories 4. Accordingly, its first item, the ‘what it is’, was identified with the category of substance. This interpretation has been challenged by several scholars, all sharing the view that the ‘what it is’ in Top. I 9 cannot be substance, since it collects items belonging (...) to all Aristotelian categories (e. g. human being, colour, length). Rather, they say, it is a manner of predication – i. e. essential predication – and can only determine an ontologically miscellaneous class of items. Against this family of proposals, I argue afresh that the traditional interpretation is almost entirely correct. To this purpose, I take advantage of the distinction between kinds of predicate and kinds of predication. (shrink)