Drugs baron-turned-author Howard Marks is battling inoperable bowel cancer.

The Mr. Nice writer was diagnosed with the disease last autumn (14) and doctors told him nothing can be done to stop its spread.

He tells Britain's The Observer newspaper, "I've come to terms with (the cancer) in my own way - which for me was about learning how to cry. It's impossible to regret any part of my life when I feel happy and I am happy now, so I don't have any regrets and have not had any for a very long time."

Marks, 69, built up a worldwide cannabis empire in the 1970s and '80s and was sentenced to 25 years in prison when he was finally busted by the U.S. Drug Enforcement Administration in 1988.

He was released on parole in 1995 and penned a bestselling autobiography based on his experiences, which was later made into a movie starring Rhys Ifans and Chloe Sevigny.