Book 4 "Davey and the Big Red Machine" The story starts with new implements for the big blue tractor Colin the County and Davey gets worried he is being left out. However there is a surprise new machine that arrives and initially Colin works this, but eventually Davey takes over. The mystery is what it does.
The section for adults at the back of this book is about "Jennifer Gipsy" the Austin Gipsy that is used to tow the trailer. It gives a brief history of how Austin developed this vehicle. The fire engine version was awesome and there a selection of photographs of these.
The "Davy" series of stories for young children in age range 2-7. These stories are based on true events and each story is lavishly illustrated with hand drawn art, not computer generated. Davey does exist as do all the characters and machines introduced. Each book has a small section at the back which is information for parents / adults about one of the characters in the book.