Rattenbury, who is also a columnist for the Whanganui Chronicle, said the book told stories of different kinds of police officers from New Zealand's history.
"There are some characters who, without them, we wouldn't have a decent police force today. These were some really far-sighted men."
Rattenbury said there was no record of a "fully sworn-in" Maori police constable in New Zealand between 1880 and 1920.
"Even the early 1960s there was still an order out that Pacific Islanders were not allowed to be employed by the police.
"Indians weren't welcome, and neither were Asian people. Māori were being recruited from the mid-1950s, but only slowly.
"That all changed in the late 1960s when a far-sighted senior officer, who was a little bit more enlightened than the rest of them, put programmes in place for recruiting from Maori and Pasifika."
Today 15-18 per cent of the New Zealand police force were Māori, Rattenbury said.
Women in the police force is another area which is covered in the book, and Rattenbury maintains that it was in New Zealand, not Chicago, that the first female police officer was employed.
"In 1892 a woman by the name of Ursula Smith was employed as a detective in an undercover role to catch a murderer.
"She didn't get quite far enough to obtain a conviction for murder, but she asked to do another job in Dunedin. The commissioner at the time decided it was probably to dangerous for women to be involved in policing, so she was given her marching orders.
"Even so, she was a paid, sworn detective. It was another 50 years before women began to be sworn in, in 1941."
Rattenbury said police history in New Zealand was well-documented, and his book was a compilation of stories from various history texts.
"These are some of the ones that really stuck out for me.
"I picked out stories, researched them, and made them readable tales, rather than boring history texts."
Stories from his own days in the police also featured at the end of the book, Rattenbury said.
"The stories that come out of policing are phenomenal, and one of the things that we always used to say to each other after we'd been to an incident was 'people would never believe what we've just done'."
His first book, 'So You Want To Be A Cop...' was a memoir on his family and career in the police force.
