He has written for most major newspapers and is the author of a series of best-selling books.
His disclosures have led to the expose of numerous rackets and the downfall of many identities, including a government minister, a police commissioner, a chief magistrate and a high court judge. 
In the words of Malcolm Brown in the Sydney Morning Herald , Bottom made "heroic, ground breaking efforts to expose organised crime" and "did more than any other single individual to bring crime and corruption to public attention in NSW in the 1970s and 1980s". At times, he and his family were afforded 24-hour police protection. 
Because of the scale of information confided to him as a trusted contact for crime intelligence operatives, Bottom has been hired to advise insight teams for newspapers including the Sydney Morning Herald and The Age and has been a known source for countless exposes by other investigative journalists, often making him a target for threats, smears and vilification.
One of his most famous exposes, the release in 1984 through The Age newspaper of material on identities and rackets from telephone taps illegally carried out by undercover police in NSW, provoked state and national inquiries and ultimately prompted governments to allow law enforcement agencies to legally use telephone interception in organised crime cases.
Over the years, he has participated in 18 Royal Commission and other judicial and parliamentary inquiries and has played a key role in the establishment of state and national institutions to combat organised crime and corruption.
He sparked his first inquiry into the New South Wales police force with an expose in The Bulletin magazine in 1963. Writing later for the Sunday Telegraph , he was credited with helping force Australia’s first Royal Commission into organised crime – the Moffitt commission in NSW in 1973 which resulted in police setting up crime intelligence units throughout Australia.
A report he wrote for the NSW Government in 1978, titled Report Upon Organised Crime In NSW, first recommended a separate crime commission concept for Australia. At that time, he had been working as a government adviser.
He was consulted by then Prime Minister Malcolm Fraser before announcing a National Crimes Commission in late 1982 and was a delegate to a National Crime Summit in July 1983 when the new government of Prime Minister Bob Hawke opted to transform the Fraser model into the National Crime Authority .
In 1986, his concept was finally adopted in NSW for the establishment of a Drug Crime Commission targeting drug trafficking and was then engaged as an adviser when it was subsequently reformed into the NSW Crime Commission to target all forms of organised crime.
In 1988, he was also appointed to a steering committee for the establishment of NSW’s Independent Commission Against Corruption (ICAC). In 1989, he was again engaged to advise on pioneering legislation in NSW for confiscation of assets from criminals involved in organised crime.
In 1997, he prepared a report which resulted in the establishment of a Queensland Crime Commission – since merged with the Criminal Justice Commission to form the Crime and Misconduct Commission . In 2002, he was involved with the reformation of the National Crime Authority into the Australian Crime Commission .
During 2004, he was a participant in a Victoria Police Organised Crime Strategy Group which devised a five-year plan to confront Melbourne’s underworld following a gangland war in which 28 people were murdered.
Now in retirement, while writing the occasional special article, he has been a regular witness before parliamentary committee hearings reviewing law enforcement efforts to combat organised crime.
In all, his work has been referred to in more than 30 books by other authors.
His latest book, Fighting Organised Crime, Triumph and betrayal in a lifelong campaign , was published in 2009.
For his work "investigating and reporting upon organised crime in Australia" he has been awarded an Order of Australia Medal (OAM) and has been made an honorary professor of journalism by Queensland’s Jschool for his "outstanding contribution to journalism". He is a recipient of a lifetime achievement award from the Crime Writers Association of Australia.