The Book

I haven't read the look in a little while but as I recall,

The book begins with the land girls in their sixties or seventies waiting for their yearly reunion at a restaurant.
The WWII action is flashback.
Prue is a lot more "promiscuous" in the book than in the movie. She has several lovers in the book. She doesn't marry anyone while working at the farm. The boy who dies is actually one of her lovers and the soldier who brought her the news becomes another. She also gets together with one of Joe's friends.
In the movie, Joe wants to enlist but is needed on the farm. When he enlists, he finds out he has a heart murmur and has a blow up at the table with his parents about it. In the book he has asthma and had already been turned down for the military. There is no big moment of him getting upset about it. The friend that Prue gets with is in the same situation.
I think Ag is a lot more likeable in the book. She is carrying a torch for a boy from college who enlisted and is really the only guy she is interested in. She sleeps with Joe so she won't have to worry about having her first time be awkward with her real love. There is no Canadian soldier in the book. After the war she eventually finds the boy from college and marries him.
Stella is pretty much the same except for the scene where she visits her fiance. They do have sex.
She and Joe fall in love, but she marries her fiance after he is injured.
The biggest difference is the ending.
The book goes back to Stella as an elderly woman. Stella and Joe have continued their affair all this time. She even had his child. They get together publicly after her husband dies.

I found the movie a little disappointing and pretty sad.