I've been given some conflicting advice about preparing book proposals and manuscripts for academic presses. I'm aware that writing books is a lengthy process etc; however, I've also been told by a friend in the research office who handles applications that to be competitive at all for [DECRA][1] and other fellowships, I need at least 9 publications and one book behind me to be considered a strong applicant. 

So I've been thinking about this book idea (cross-disciplinary social sciences/cultural studies) for awhile, some of which would come from my PhD, other bits as new material. It is something I would like to write, not for money, mostly for myself, somewhat for career. I submitted a brief enquiry to a potential publisher who said they'd be interested in seeing a book proposal on the topic I offered which I have the template for.

My question concerns whether the book should already be written, or if a proposal and sample material can suffice in early stage? Some colleagues have told me that the latter is preferred, I don't need to have a complete manuscript prepared. Advice online is conflicting, some telling me I should have a whole manuscript prepared as an ECR to be ready to submit, others telling me only a partial is fine. 

Any guidance would be appreciated! 

**Below responses were not helpful:**

 - http://academia.stackexchange.com/questions/21407/is-it-bad-practice-to-submit-the-entire-manuscript-for-an-initial-book-proposal 
 - http://academia.stackexchange.com/questions/1412/what-are-the-most-important-points-to-emphasize-while-pitching-for-a-dissertatio
 - http://academia.stackexchange.com/questions/57516/publishing-thesis-as-a-book
 - http://academia.stackexchange.com/questions/5426/when-to-publish-a-book
 - http://academia.stackexchange.com/questions/49751/publication-strategy-for-book-manuscript
 - http://academia.stackexchange.com/questions/6086/how-do-i-convert-my-phd-dissertation-so-that-it-can-be-published-as-a-book

  [1]: http://www.arc.gov.au/discovery-early-career-researcher-award