I think in such an edge case with such wildly divergent fields you could represent yourself - though if they are going afer you for a book you wrote it's likely you are published author and publishers have lawyers too.
Where it gets trickier is if you work as a devloper and they go after waht you have done in the evenings
Where it gets trickier is if you work as a devloper and they go after waht you have done in the evenings