Horton Plains is part of a UN declared Central Highland World Heritage site and is Sri Lanka's most visited national park. Most people visit the plains for its beautiful scenic spots including the World's End cliff and Baker's Falls.
But there is more to it than meets the eye, which the book aims to show.
"It is really a fantastic piece of forest and landscape in Sri Lanka because there are so many endemic animals and flowers and plants," says Pethiyagoda, a researcher who had himself discovered a described a numerous new species.
"That is it a really special place. To that you then add, the fact that there is all this history to it. Stone Age people lived three 18,000 years ago. There are stone tools, they had herded cattle there."
About 20 people who specialized in several areas had contributed to the book which was 15 years in the making.
Savitri and Nimal Gunatilleke, Gehan de Silva Wijeyeratne, Sudath Nanayakkara, Michael & Nancy van der Poorten, Madhava and Suyama Meegaskumbura, Dinarzarde Raheem, Kelum Manamendra-Arachchi and Udeni Jayalal had helped write the book.
The 320 page book has more than 500 photos, over 100 drawings and 75,000 words, describing plants, birds, dragonflies, butterflies and small mammals like mice and shrews.The contributors to the book had taken great pains to photograph some of the species which are small and nocturnal.
"It tries to tell the story," Pethiyagoda says. "You will be able to identify any animal or bird of flower that you see and you will be told a story."
The Horton Plains plateaus was discovered and made known to the outside world in 1834 ater two British army officers spotted the plains from Piduruthalagala, a nearby mountain peak which is more than 15 kilometres away.
"They saw this plateau and they thought we must go and explore. They were so excited when they finally climbed Horton Plains and saw this lovely plateau," Pethiyagod sasy.
"They thought first of cultivating vegetables - because it was so much like the British climate - of course they did not thankfully."
It was named after then British governor in Sri Lanka and its discovery was published in the government gazette.
Over the years the plains had become the focus of attention of many botanists and zoologists had visited and done work there.
In 1882, Enrst Hecker, a German evolutionary biologist had visited the plains.
"He was the last man to see elephants on Horton Plains. We even know the date, 24th of February 1884. He was there and drew the picture. I got it from his library in Germany."
The Plains is a fragile environment which is also facing a number of threats and increased awareness of about the richness of the plains would help its conservation.
Unlike other national parks coming under Sri Lanka's Wildlife Conservation agency, in Horton Plains visitors can walk on foot.
"The difference when you can go on foot is that you have a much more intimate contact with nature," says Pethiyagoda.
"You get wet, you get muddy, you can right up to whatever you are taking a photograph of And it is a much more intimate contact, especially for children.
"The reason we did the book was to help people who go to the plains to get a better understanding of what it is all about."
Tokyo Power, a biomass power unit of Sri Lanka's Tokyo Cement Plc, is sponsoring 300 copies of the book to school libraries in Sri Lanka. Tokyo Cement chief S R Gnanam, a keen birdwatcher and a schoolmate of Pethiyagoda.
"We are already working with schools about renewable energy," Gnanam said. "So along with it we can distribute this book. We hope to work with student clubs."
The book is also in the process of being translated into Sinhalese.