The other looks at those issues which are driving today's health policies, such as spiralling costs, new technology and ageing populations.
Prof Gauld, of the University of Otago's department of preventive and social medicine, is also expecting two more books he co-authored to come out next year.
He had hoped all four books might come out in the same year - which would have been a career high - but unfortunately it did not happen, he said.
The New Health Policy, published in June, examines the health policy challenges facing health systems in the developed world.
While countries such as New Zealand, Australia, the United States and Britain were all facing the same challenges, each country approached the issues quite differently.
In New Zealand, questions such as whether healthy eating and keeping active were more important than access to surgery had been highlighted by the shift in government from Labour to National.
One chapter covered issues around information technology, a subject to which Prof Gauld has previously devoted an entire book.
Information technology had "enormous implications" for health systems, but New Zealand had "really lost its way", he said.
"We are still bogged down in debates about data privacy and security, what kind of data can be shared and who's going to pay for it all.
"Really good health systems have nationalised electronic health system records."
However, despite the troubles in New Zealand's health system, the country "actually does pretty well" in terms of crude indicators, such as life expectancy, disease incidence and mortality rates, Prof Gauld said.
Prof Gauld's second book, Revolving Doors: New Zealand's Health Reforms - The Continuing Saga, published in May, is a second edition of a book that first looked at the series of significant health reforms in New Zealand since the late 1980s.
Those reforms covered the changes from area health boards, to regional health authorities and Crown health enterprises, to the health funding authority and district health boards.
The new book includes material about the performance of district health boards and primary care reforms, which is based on "boxes and boxes of files" obtained from the Ministry of Health under the Official Information Act.
The new chapters were essentially an assessment of the Labour Government's record and what "they attempted to set in train with district health boards and primary care reforms and the creation of primary health organisations," and an overview of the National Government's performance from the last election to last March.
This year Prof Gauld intends to concentrate on publishing academic papers.
