As a child growing up in Ohio, American venture capitalist, author and philanthropist Gregory Slayton was abandoned by his father along with his two younger brothers.

"Dad was quarrelling with mum all the time at home and would disappear for months often," he said. "He was bad, and drank too much."

When he was in his teens living in Long Island near New York where the family moved to, he got a letter from his "quite successful company executive" father telling them he would be leaving for good.

This did not put 56-year-old Mr Slayton off fatherhood, but instead inspired him to promote its importance later in his life.

He even wrote the best-seller, Be A Better Dad Today! in which he says a father's job "is the most important a man will ever have".

The book has sold more than 200,000 copies since it was published three years ago and was translated into Chinese this year.

In 2011, Mr Slayton started the Fellowship of Fathers Foundation in North America to coach individuals and partner corporations or community groups interested in making better fathers of their members or employees.

He has been married to education lecturer Marina for 26 years, and they have four children aged 14 to 25. His foundation had its origins in the Slayton Family Foundation he set up with his wife in 1999 to help fathers and charities. It was set up thanks to the financial success of his firm Slayton Capital, which advised companies such as Google.

Two years ago, the fellowship expanded into Asia as Family First networks, a group of non-profit organisations committed to training family coaches. It has affiliates in Taiwan, Indonesia, the Philippines and more recently in Singapore (see other story), with thousands of fathers benefiting from its programmes.

In Singapore to promote the company's work last week, he told The Sunday Times he has a Taiwanese-American family to thank for his passion for good family living and the importance of fathers.

The Changs lived near him when he was a teenager and their father, who ran a general merchandise store, had treated him like his own son. He remembered Mr Chang as a "very traditional Chinese man who didn't get drunk, didn't throw things at his wife, was super hardworking and took his family to church every Sunday".

"Compared to my own dad, he was fantastic and a good role model for me," he said.

Mr Chang, who has three sons, is now 83 and living in New Jersey.

Mr Slayton, a Fulbright scholar, ran an orphanage in Manila and helped the poor in South America before going into business. He was US Consul-General to Bermuda from 2005 to 2009. He now lives with his wife in Hanover.

He said the book, with all its tools and ideas, "will still not make perfect fathers", however. "We just have to keep trying to be one."

Now he and his wife want to help women to be good mothers. In April, they published their first book together, Be The Best Mom You Can Be.