Paul Baker likes being in control.
His speech is slow and measured when he muses on analysing data and self-assessment.
He has put words into the mouths of professional actors, commanded the stage himself, and helped to revolutionise boys' schools in New Zealand.
He has held numerous positions of authority, held annual exhibitions of his photographs and has a scholarly pen.
He sits composed on his office couch with one hand in the other.
But he cannot stop his right hand from shaking.
And his time as rector of Waitaki Boys' High School is coming to an end.
Dr Baker first experienced symptoms of Parkinson's disease three years ago, but was only formally diagnosed earlier this year.
"It certainly has gathered momentum this year, which is why I am retiring earlier than I had expected," he said.
"I start off the day usually with a burst of vigour that lasts about an hour and then it's steadily downhill and evening meetings are quite a challenge.
"I start to physically slow down, my feet want to shuffle - they don't want to walk any more. My hands want to clench up; there's a lot of things.
"If we were having this interview at nine in the morning, I wouldn't be talking as slowly as this - this is not my normal.
"It probably sounds to you as if I'm being deeply reflective, but I'm just slow."
Dr Baker said there was no definitive test that proved a person had Parkinson's disease.
His diagnosis was the result of many tests over a two-year period that eliminated what the other causes of his symptoms might have been.
The news finally came at the beginning of the year as he was seeking medication for his tremor, which was preventing him from sleeping.
His condition, which is sensitive to stress and fatigue, has worsened this year and he has agreed with his neurologist that it is time for him to retire.
"Some parts of my brain seem to operate just as normal - fortunately for me, the creative part of my brain seems to be unaffected - but other parts, to do for example with planning, I now find quite a struggle.
"The executive side of my brain, the organising side, the side that tells where to put pieces of paper is now quite lethargic as is evidenced by my desk."
Change is nothing new for Dr Baker, who has overseen a period of rapid transformation at Waitaki Boys', and in the education sector, since he took over the helm in 1999.
"I've always been a big believer in starting things off to see how they will develop. Planting seeds and seeing how they grow, adapting, amending as time goes on," he said.
"I've never been a big believer in five-year plans, or three-year plans and knowing exactly where and how something is going to develop. You can't predict that because you're working with human nature."
He said boys' schools had essentially reinvented themselves, with spectacular success, as places "where a whole variety of different models of masculinity are promoted".
The model student is now academic, cultural and a sportsman, "but the hope always is that they are one and the same person".
His tenure has coincided with the reverse of what had been a steady decades-long decline at Waitaki Boys' High.
"The school used to have a roll of 900 in the 1960s and then a whole combination of factors saw it go down by 20 or 30 or 40 every year for at least 20 years, which was soul-destroying for some people," he said.
"That's in the past.
"In the start of 2010, we got put in the top Education Review Office [ERO] category and came first amongst the boys' schools in NCEA, and that happy coincidence was a wonderful affirmation to the community of the good work of the staff."
Positive change comes from constantly fine-tuning every aspect of an operation, he said.
"If you are looking at the process of change over 13 years, you are probably looking at a list of 200-300 things . . . there are no five or 10 things that you can point to as being the key agents of change.
"We have a very analytical culture at this school. There's a lot of what's called self-review. We look at everything.
"One of the benefits of a small school with a roll of about 500 is that it is possible to micro-manage.
"It's also in my nature to want to micro-manage so it's a good match of personality and school, I suppose."
Board of trustees chairman Bill Wright described Dr Baker as the "ultimate educator for boys" and a visionary whose contribution to the school had been "absolutely amazing".
Dr Baker was the "ultimate professional" and had given the school plenty of time to find a suitable replacement, Mr Wright said.
"We've got to be positive and look at it as the next step in the school's history.
"Hopefully, we can find someone equally as good. It will be a huge challenge," he said.
With retirement looming, the rector used to driving change must deal with having it foisted upon him.
Self-assessment has taken on a different meaning, and decisions must be made on just what can be controlled.
"One thing that goes is your voice. I sang a lead role as Pontius Pilate - an anguished authority figure quite easy for a principal to do - in Jesus Christ Superstar, but I couldn't do that again," he said. "My singing voice is going; it's got very thin.
"Essentially, I need to be able to live life in the slow lane rather than the fast lane and get very, very fit."
And he still is not a fan of three- or five-year plans.
"When you've got Parkinson's, you really have no idea what the future holds. I could be functioning reasonably well in 30 years' time or . . . I met somebody who had Parkinson's for five years, and his life is extremely restricted."
Still, Dr Baker is counting his blessings.
"I've been fortunate to achieve a lot of the things I wanted to achieve already.
"I consider myself very lucky. Just as one door is closing, another door seems to be opening. My second play [Meet the Churchills] was a success, commercial and critical, and that's encouraged me to carry on and I get great satisfaction from writing plays.
"I've got several more on the boil, and so I'll be a semi-retired playwright."
He will continue to live in Oamaru and is looking forward to spending more time with friends and family in Auckland.
He also intends to travel and live for a time in England, which he had done before and loved every minute of.
But he has yet to put the finishing touches on a legacy that many in Oamaru are comparing to that of the renowned Frank Milner, who led the school for 38 years from 1906.
Walking around the school's quadrangle on the way to the Hall of Memories, gently reminding the Otago Daily Times the grass is not to be walked upon, he suggests a spot where a photo should be taken, and pauses momentarily.
"I'm not quite ready to leave yet," he said.
The Baker file
• Age: 56.
• Born: England.
• BA in history and political studies, Auckland University, 1975.
• PhD in history Auckland University, 1986.
• Began teaching career at Auckland Grammar in 1985.
• Began as rector of Waitaki Boys' High School in 1999.
• Helped to establish the Association of Boys' Schools of New Zealand in 2003, and elected first chairman.