Writing: The Purpose of the Introduction, Summary, and Conclusion

Tell them what you’ll tell them, tell them, then tell them what you told them.

This advice, although well meaning, isn’t always the best approach. Although repetition has its place, repeating information three times is by no means the gold standard of teaching. I want to explore a different and perhaps more interesting way of conveying information.

The Introduction

This connects your topic or thesis to something broader that the reader is already familiar with. In other words, it places the topic in a context that the reader recognizes. At this point you might think, “My reader already knows the context, or at least they should.” This is often the case with a book where you expect the reader to have read previous chapters (or posts, or whatever designation you’re using to break up your content).

But why do chapters exist? Originally their intention was to provide a way to locate information in a book. That’s still their primary purpose, although authors use them to give the reader a natural stopping point. In fact, I’d venture that most authors expect readers to work through a chapter in one sitting. Hence, as authors, we rightly expect the reader to remember the context of a chapter while they’re in it. But it’s not necessarily reasonable to expect a reader to remember the details of the previous chapter when starting a new one. Using the introduction to restate relevant information from previous chapter gives you additional freedom later on, knowing that you and the reader are on the same page. You don’t have to interrupt your epic flow with an, “Oh by the way, remember that thing you read about 8 chapters ago? Let me remind you.” Get that out of the way in the introduction.

But what about cases where the topic you’re writing about isn’t connected with previous chapters? Perhaps you’re bringing in a completely new idea. This is the case with “check the box” content like textbooks that need to cover various unrelated topics. You need to tie the topic into your reader’s existing context. But how do you do that when you don’t know what their context is? For example, suppose you’re writing about an information security product that uses machine learning to detect and respond to threats. Does your reader know what machine learning is? Do they understand what a “threat” is?

You have to make some assumptions about what your reader already knows. If you assume they know little, you’ll need to fill them in at the risk of stating the obvious. If you assume they know everything, you may go right over their heads and lose them at the beginning. A rule of thumb I like to use is this: tell them enough to make them feel smart if they’re with you, and lost if they’re not. For example, you may say something like, “Our product uses machine learning to analyze attack patterns from around the world to predict and stop new emerging threats from hackers attempting to steal trade secrets.” In doing this, you’re doing a couple of key things:

First, you’re forcing the reader to categorize himself. The reader who thinks, “I get what this means,” will feel smart and – if interested in the topic – will keep reading. The reader who thinks, “What the heck is an ‘attack pattern?’” is going to realize they’re not in the right place, and will backspace and go elsewhere.

Second, you’re giving the rest of your chapter (or article) a direction. Actually, it’s more like you’re pointing it in a certain direction and getting ready to kick it hard in the rear. Once you pen your introduction in the way I’ve described, there’s no going back. And there’s freedom in that. Your reader won’t expect you to go elsewhere.

There’s another advantage to projecting the direction of your chapter. People often think they know things they don’t. It sounds weird, but people who casually read about topics (rather than deeply studying them) tend to develop incorrect conceptions of those topics, especially when it comes to technology. This is your chance to correct those misconceptions, and also establish your own credibility. A reader who thought “machine learning” was computers developing emotions and laughing at jokes will feel satisfied having learned that it’s just a type of predictive analysis.

So, the introduction is not where you “tell them what you’re going to tell them.” Yuck.

The Summary

You probably won’t fall out of your chair if I tell you the word “summary” means sum or substance. Basically, it means everything you covered in the chapter minus the junk. This is the definition of “tell them what you told them”.

I know what you’re thinking: “I don’t have any junk or fluff in my writing. It’s all important.” You’re right. So what’s the point of a summary? The only time you should use a summary is when you’re summarizing someone else’s content. Summarizing your own content is like washing your hands, drying them, then immediately washing them again. It makes no sense. The obvious takeaway is don’t write a summary. Instead, write a conclusion.

The Conclusion

When people say “summary” they almost always mean conclusion, which means “outcome,” “deduction,” or “inference.” Do you see the pattern? The conclusion takes your topic and considers the implications of what you’ve written.

Remember that the introduction is where you point your topic in a specific direction and give it a swift kick. Well the conclusion is when your topic reaches a fork in the road. There’s a balancing act here. You’ve taken it as far as you want to for the moment, but now it’s time to advise the reader on where this topic could (or should) lead. If you’re writing a book in which the chapters are topically connected, this would be the obvious place to hint at the next chapter. This is the place to pontificate about the implications of the topic, to get “meta” if you will. This will naturally require restating some points about it. For example, if you want to wax philosophical about how government-sponsored attacks are more sophisticated and harder to detect, you’ll naturally have to revisit the technical details of cyber attacks.

For people like me, delving into related ideas will lead to the inevitable, “Maybe I should add this to the chapter.” Don’t. It’s the equivalent of rambling. The goal of the conclusion is to close out the discussion of the topic at hand, while opening (and leaving open) the implications of your topic. Your conclusion is not the conclusion. It’s okay to leave some things open ended.