Strategy, discovery, metrics, growth, pricing, design, delivery and leadership. Each entry says when it is the right one to pick up.
Lauchengco's product marketing book, part of Cagan's Silicon Valley Product Group series. Defines the role through four fundamentals of ambassador for the customer, storyteller, evangelist, and connector to go to market strategy.
Dunford's ten step process for positioning, treated as a deliberate exercise rather than a byproduct of messaging. The components are competitive alternatives, unique attributes, the value those enable, the customers who care most, and the market category you frame yourself within.
Ries and Trout published this argument in 1981 and it has been in print since. The claim is that a position exists in the mind of the buyer and never in the product, so the work is finding a position that is open rather than describing what was built.
Dunford's follow up applies positioning to the sales conversation. The structure she proposes moves from insight, to the alternative approaches available, to the perfect world criteria those imply, then to the product as the way to meet them, followed by proof and objection handling.