What is the fine-grained topic of the following text: All you need to do in order to get a ‘beta’ invite and be among the early adopters of this new platform (skipping the queue ahead of those who sign up for beta on the OpenBook website) is sign up to my free, no obligation, quarterly author newsletter if you haven’t done so already. Only return the topic.
Signing up for a beta invite to a new platform via an author newsletter