Hi Kitty,
It took me a couple days to mull over your question and read Nomad's responses, but your situation is very similar in how I constructed my first book.
Like yours, my first and third books were built largely from research. I'd like to tell you how I did it, and maybe it'll work for you, too.
I typed up the rough draft in a logical progression based on the research materials, taking the ideas and information and just typing them down. Periodically I would use a direct quote if I felt the passage called for one. After the first draft was finished, I rewrote and revised, adding transitions and conclusions, but trying to keep everything objective at the same time.
After numerous rewrites and revisions and further rewrites, I had a draft that no longer resembled anything from original source material. Each chapter was now a story with a beginning, middle and end.
Once the publisher had it, the editor made further suggestions and did further editing, and what resulted was a very readable history book.
So, that's what I did. If you follow the link from my signature, you can see the books in the AW library. You can also read excerpts on amazon and google books to get a further idea of how I wrote the text.
Hope that helped,
allen