The former treatise [ton men prOton]. Literally, the first treatise. The use of the superlative is common enough and by no means implies, though it allows, a third volume. This use of [prOtos] where only two are compared is seen between the Baptist and Jesus (Joh 1:15), John and Peter (Joh 20:4). The idiom is common in the papyri (Robertson, Grammar, pp. 662, 669). The use of [men solitarium] here, as Hackett notes, is common in Acts. It is by no means true that [men] requires a following [de] by contrast. The word is merely a weakened form of [men] = surely, indeed. The reference is to the “first treatise” and merely emphasizes that. The use of [logos] (word) for treatise or historical narrative is common in ancient Greek as in Herodotus 6 and 9. Plato (Phaedo, p. 61 B) makes a contrast between [muthos] and [logos]. I made [epoiesamen].