This is a perfectly good English sentence, but the verb 'to tackle' doesn't mean quite the same thing as 'to be about'. When a book or article "tackles" a subject, that generally implies that the subject is a very extensive, difficult, or complicated one, and can also imply that the subject matter might be socially, politically, or culturally sensitive or controversial.
To be quite proper about it, a book would also probably tackle a subject rather than a thing. 'Thing' would certainly be understood, but it sounds a bit generic.
That is an old-fashioned and now unusual way to say it. (And I think it needs a preposition, "treats of" or "treats on" I think? That may be incorrect, as I said, it's very unusual today.)
Regarding its origin for that usage, the online dictionary says: ORIGIN Middle English (in the senses ‘negotiate’ and ‘discuss a subject’): from Old French traitier, from Latin tractare ‘handle’, frequentative of trahere ‘draw, pull’. The current noun sense dates from the mid 17th century.