Eoin Colfer used this latter concept but none of the plot ideas from The Salmon of Doubt .
Eoin Colfer wrote the sixth book in the Hitchhiker 's series in 2008 -- 09 .
Eoin Colfer , who wrote the sixth book in the Hitchhiker 's series in 2008 -- 09 , used this latter concept but none of the plot ideas from The Salmon of Doubt .