Before we print a book at the Prags we usually release it to beta and we always send it to tech review. Most of the comments we get are useful. Having lots of eyes on a document is definitely a good thing. One category of comments puzzles us. A reader will write that on page such and such we mention some topic and this is the first time we mention it so we should explain it better.

So what’s wrong with that?

Well, often it’s a topic that we thought the author introduced pages earlier. The term was explained along with a bit of the context. The reader just missed it.

I was at a small zoo this past weekend and saw this sign inside of the pen that held the Kangaroos and Wallabies.

The animals were great. We were able to get as close to them as you are to this screen. The humans were a bit odd.

We watched as family after family entered the pen and stopped to read the sign. Then they walked around and looked at the Kangaroos for a while. They then moved on to where we were standing and pointed at the Wallabies. Every single family said "look at the baby Kangaroos."

There in the zoo there wasn’t much different that could be done short of hanging a sign on the side of the Wallabies that said "I’m not a baby Kangaroo. Don’t you remember that big sign that was posted when you first came in."

In our books, however, we can do something about this. We can point the reader back to where we introduced a concept or used the same idea in a different setting. You can also make a reference to a concept you are using in contrast, "remember when I made you do this ridiculous thing by hand? Now we can use the built in libraries to do it automatically."

Often it’s not that the reader missed something it’s that they don’t remember that they read it. Help them out by setting the context. You are helping them fill in a map. You know the entire lay of the land and how everything fits together. They’re just figuring out that this place you drove them to a couple of chapters ago is just down the street from the place you’re showing them now.

This post originally appeared in the Pragmatic Life blog.