by Alison Ford
Question: Does a non fiction book have to have a forward?Answer:
Certainly not. With some types of non-fiction, such as business books, it is helpful to have an introduction that summarizes the main message of the book simply because people who read business books often don't want to invest the time in reading an entire book unless they have to or really see it as valuable. They tend to read the introduction to get the main idea and then skim the rest to get the essential points. (These readers often "read" a dozen books a year in this way.)
On the other hand, history readers tend to read for enjoyment, are more willing to invest more time in a book, and may not need such an intro.
It can be helpful for marketing purposes, especially if the author is not famous, to have a forward written by someone else who is. It's a way to get a famous name on the cover ("Forward by..."). With first books, some authors will show the manuscript to a few well-known experts to get some endorsements or possibly a forward.
How essential this is depends on the book, audience, etc. Your publisher might have some recommendations/demands in this area.
You might also look at some books in your niche genre to see if there are common format elements which readers expect. Then see if those elements make sense for your book.