Quoted from JoeDP:
You seem like the kind of person who might be remiss if we skipped an important subject. If you are you can get involved now, before it's too late to change the book
Whatever topics you decide to focus on regarding Stern I have no doubt will be vetted properly and sufficiently with Stern management.
Your title of the book, says it all, as it is a history.
If there are any people that could provide insight in writing pinball books (not just knowledge, technical aspects, and history) it would be Rossignoli.
He knew how to incorporate both good background and high quality photos in a cohesive package and his book took YEARS to write, so the timeframe shown here is quite short, especially for any potential new photography.
I have self and professionally published myself for technical and thesis work based on requirements of research, which also was very time consuming.
Maybe Stern has an entire data library categorized with all their accomplishments and details to make it easy for your behalf, I don't know, as I never have asked this question, especially as staff has changed fairly regularly over the past 15+ years.
This certainly would speed things along.
As much as pinball is a "passion" to me which has turned me more into a pinball historian now, and my experiences of 30 years of collecting, I can only tell you one small piece of advice. Don't exclusively focus heavily on games designed and created the past 5 years, as this is not a comprehensive look at the manufactured history of Stern, or their relationships (pseudo or not) with Bally/WMS, DE, GTB, and Sega, nor the actual support that was provided by both collectors, owners, and operators that shaped Stern into what they are today (during the dark times). They did not survive by being alone.
It is too easy for an author to trap oneself based on the simplicity of finding games that fall into this "recent" category and locally well known by new owners today. Some of the most interesting Stern history took place long before games such as Tron.
Only a few people are left now that know the whole sets of stories.