and it sounds as though the basis for seeking the injunction was on the basis that the information contained in the proposal was a "trade secret".
An idea for a book does not fit neatly into the definition of a trade secret.
A trade secret is generally defined as "information that derives independent economic value from not being generally known or readily ascertainable. Among the things that can be trade secrets are a formula, pattern, compilation, program, device, method, technique, or process."
The types of factors that a court looks at in determining whether something constitutes a trade secret are:
"the extent to which the information is known outside the business;
the extent to which it is known to those inside the business, i.e., by the employees;
the precautions taken by the holder of the trade secret to guard the secrecy of the information;
the savings effected and the value to the holder in having the information as against competitors;
the amount of effort or money expended in obtaining and developing the information; and
the amount of time and expense it would take for others to acquire and duplicate the information."
One can certainly assert proprietary rights in one's ideas. But it appears that if a person wants to protect an idea as a "trade secret" there are several criteria that have to be met, not least of which is that the person has to take active steps to prevent access to the idea and to preserve the secrecy of it.
It is not enough to just say, hey, I didn't give Mr. X permission to hear about my idea or to read it or to report on it and therefore it is a trade secret. The person seeking protection of the info as a trade secret is required to do things to prevent the info from being spread around. Such as, for instance, obtaining non-disclosure agreements from those to whom the person tells the secret info and from those who might gain access to the secret info, or marking the material with a proprietary legend restricting the use and disclosure of the information, and taking care by means of other positive steps to prevent the secret info from falling into public knowledge.
There is a straightforward kind of primer in lay terms at this link:
http://law.freeadvice.com/intellectual_property/trade_secrets/Hope that helps!
And in the meantime, I still hope that an IP lawyer stops by to correct anything I may have got wrong :D