Olivia Judson 's book looks at animals' sexual behaviour

Two first time authors are included in the shortlist for the BBC Four Samuel Johnston Prize for Non Fiction for 2003.

Olivia Judson, nominated for Dr Tatiana's Sex Advice to All Creation, and Edgar Vincent, for Nelson, are both first-time authors.

They join a list which includes Claire Tomalin's biography of the diarist Samuel Pepys, Samuel Pepys: The Unequalled Self, which won the Whitbread Award earlier this year.

Other nominated writers are Orlando Figes' Natasha's Dance and TJ Binyon's Pushkin.

And Aminatta Forna's The Devil that Danced on the Water completes the list, announced on Thursday. The prize, worth �30,000 for the winner, will be handed out on 9 June at the Savoy Hotel.

Claire Tomalin and husband Michael Frayn were up for the Whitbread award

The traditionally heavyweight list this year recognises Judson's relatively light-hearted book about sexual behaviour in animals, which is written in the guise of an agony aunt answering animals' sex questions.

Judson is an Oxford-educated evolutionary biologist, and answers questions such as why stick insects have sex for 10 weeks at a time.

'Excellent list'

The book has already been a big success in the US, and Judson has already started a TV career there.

Rosie Boycott, the chair of the judges, said: "This is an excellent and strong list. Although fewer science books made the longlist, we are delighted to have Dr Tatiana's Sex Advice to All Creation on the shortlist.

"Each book brings a different perspective on life - and we would urge everyone to seek out and read these books, even before the winner is announced."

Claire Tomalin was a controversial winner of the Whitbread prize as her husband, the novelist Michael Frayn, had been listed for his book Spies.

Judges for the prize include Boycott, Kensington and Chelsea MP Michael Portillo and historian Tim Radford.