The devil is in the details
You will not make as much as it is worth, in all probability.
Contract is essential. Draw it up and see if he fusses. Know what is negotiable and what is not.
Some points to consider.
Who owns the rights, including right to show excerpts as examples of your work?
Are you expected to do the complete project, including layout, any pictures, negotiating with a printer, press runs, hardback, paperback, soft cover, dimensions of the finished work? Advertising included? Some do to defray costs.
You have to know what he expects and wants before you can even begin to set a price. Don't make any preliminary offers till you know exactly what he expects.
Target market? How many copies does he expect to produce? Is it a giveaway that the organization will eat the cost? Unlikely, but you need to know.
Deadlines, penalty clauses, payment schedules? Is he thinking the anniversary is in June of this year and you will be done by then with a complete, printed book?
Your mantra should be: Good, Cheap, Fast....pick any two. Think about it.
There should be several discussions here about contracts and or/projects. Check them out.
Main point, I get the impression you're worried about giving him a price quote tomorrow. Don't. Don't. Don't.
You have (or have not given here) nowhere close to what you need to know to quote a price. Get the information you need from him and tell him you will crunch the numbers for what he wants within 24/48 hours.
Do make an itemized breakdown of what he wants and calculate what it would cost you.
Do not give it to him.
You will be nitpicked to death.
If you continue freelancing, you will have several "template" contracts to draw from.
Make sure you calculate cost to you and some profit. My next suggestion is add a percentage to that so you will have negotiating room. (Some may disagree with this, but you are the one that will have to do the work. There are always surprises.)
This is just a brief review, others will add other concerns, just don't try to set a price under pressure without full information on expectations. If you ignore everything else, remember that. HTH