Sep.11 (GMM) David Coulthard has fired a salvo in the direction of formula one countryman Lewis Hamilton, as they prepare to also do battle in the book shops of the world.

After fourteen seasons on the grand prix grid, F1's oldest driver recently launched his biography, entitled 'It is what it is'.

Rookie championship leader Hamilton, meanwhile, last week reportedly penned a seven-figure publishing deal for his own book -- after not even twelve career races.

"I told him I was quite surprised Ron Dennis was letting him do it because he never liked drivers doing books when I was there," 36-year-old Coulthard said in an interview on Monday with The Guardian.

"Lewis said: 'Yeah, but he's not paying me enough. I've got to earn my money somewhere else.'"

In the interview, Coulthard questions Hamilton's priorities as the 2007 title battle whittles down to a contest of just four final grands prix.

The Red Bull driver said: "When I started in formula one I was just happy to be racing. Money never came into the equation."

Scotland's Coulthard also revealed that he sympathises with Fernando Alonso this season, after the Spaniard walked into McLaren some nine years into Hamilton's long association with the team.

"When I was at McLaren they blatantly favoured (Mika) Hakkinen," Coulthard revealed.

"When they cheered my teammate for beating me it tore me up. Ron's mantra is 'We exist to win' but it's not the way I do business," he added.