For this unit Refers to Student’s Book pages Writing headlines

Students discuss the questions in pairs and then feed back to the class.
 Answers
1  It is an extremely short description, consisting of one or two sentences, of the 
general idea of the story; it is the principal aim of the story that the writer 
wants to convey to the audience. (Note that a 
logline
 is not the same as a 
tagline
, which is a phrase that can accompany a film when it is released;
 
for 
example, the tagline to the film 
Shrek
 was
 
“The greatest fairy tale never told”.)
2  It can help the screenwriter clarify his/her ideas; it gives film executives an 
instant idea of what the film is about.