There is a large market for non-fiction reference books based on topics taught in school. I recently ran a workshop all about writing for educational publishers. Today I thought I would share some tips.
I think one of the main points is that educational publishers prefer to come up with their own ideas in-house or work through book packagers. I work a lot to commission. My book, Explaining Diabetes, which was published by Franklin Watts but, was commissioned by the book packager Bender, Richardson and White. It was one book in a series of books about illnesses and conditions.
When approaching publishers with unsolicited non-fiction it is better not to have a finished book. A one-page outline giving a brief breakdown of the chapters, target audience and potential market is generally what is required.
I suggest you market research the publishers you want to submit to as well. Check they publish books for the age range you want to write. There are different publishers for primary than secondary aged children. You can find out which publishers print what by checking out The Writers and Artists Yearbook.
It is wise to look at what books are out there and analyse them to see how each book is divided and what sort of things are included on each spread. Look for patterns as an indication of style and what might have been in the brief the author was given. Then try and use this as a template to plan your own book that would fit the series.
Why not try it for yourself. If you are successful please let me know.