This is an excellent book on the topic, and possible textbook material. Epstein gives a broad overview of television writing as a business, along with a narrower focus on the actual craft of writing for the medium. The book oscillates between this generalized overview and very specific advice about the actual craft, striking a nice balance where most similar books fail to do so. Most of these books are exclusively focused on the US industry, but Epstein is the creator of the Canadian Showcase series Naked Josh so he includes some small notes about the differences in the Canadian industry. It's more CanCon than any similar book I've seen, but still almost totally US-focused.