The introduction to your thesis is the first thing the examiner will read. It's your only chance to form a first impression, if the examiner doesn't already know you. It sets the background, context and motivation for your work. And so it's at least as important as every other chapter.

And yet a lot of people leave writing the introduction till last, writing in a rush just before the deadline. This is a mistake. If you write your introduction as a hurried afterthought, or as just a dry list of things that will be covered later then they will want to skim read it to get to the proper work in later chapters.

It is far better to write an engaging introduction, having spent time thinking about why your research matters and why anyone would want to read about it.

Why you might write the intro last

If you are writing chapters but you don't yet know the full story, then it might make sense to write the introduction last.

If you're doing this, I guarantee you will be stressed in the run up to submission. Why? Because you're trying to finish the research and the writing all at the same time.

It's like cooking for a dinner party and constantly running out to buy ingredients while the guests are arriving. It's not going to end well!

Stop, finish your research, then resume writing once you know what you're going to say.

Writing an engaging thesis introduction

The job of the introduction is to make the reader want to read the rest of the thesis.

Examiners are busy people. When your thesis arrives on their desk, there will be that moment of dread... will this be an interesting read, or will it be like wading through wet cement?

A good thesis introduction will set up a sense of anticipation. Why is this work important? And why should anyone care?

Here are a few tips to help you write an engaging introductory chapter:

1. Start with the big picture

Start with an idea of how the whole thesis will be structured. What will be covered in each subsequent chapter? Then when you talk about specific concepts in the intro, you can say "this will be discussed further in chapter ...". Without these references to what you will cover later, the examiner might be wondering, "why are you telling me this?"

2. General > specific > general

A good structure to follow for the chapter is to start broad. Why does your field of research matter to the wider world? Then you can talk about specific things related to your niche, and say why those matter to your field of research.

Then at the end of the chapter, try to link your specific niche back to the general, wider world again.

3. Give them something unexpected

Examiners have read a lot about your subject, but they don't know you.

Give them something unexpected; a unique perspective, something that interests you or that you find fascinating, and they will be interested to read more.

4. Set boundaries

At some point early in the chapter (but not necessarily the first paragraph) tell the reader what you will cover in the chapter.

In my thesis, I included the following paragraph after a brief introduction of about 2 pages as to why nanoscience and nanotechnology matter:

Though there are several excellent general reviews of nanoscience and technology(3–6), each to some extent reflects the authors’ personal research interestsand expertise. Due to the pace of development and breadth of research,a truly comprehensive review is probably impossible, and certainly beyondthe scope of this thesis. The following brief review presents the properties of semiconductor and metal nanostructures, in addition to the principles ofself-assembly and self organisation.

So I set out clearly what the review would cover, while pointing the reader to more general reviews for reference.

This meant I could be highly focused on specific principles, but also relate these back to the general motivation of the field.

It helps if you know what you want to cover and how it relates to your research!

5. Relate your work to the best in the field

When you talk about the state of the art in your field, focus on the very best work.

This not only reduces the number of papers you have to reference, but it gives your thesis a feeling of quality by association. It shows that you have some standards and appreciation for good research.

Say why that work matters, and you help to justify your own.

6. Where are the gaps?

Once you've talked about the best work in the field, what gaps in the knowledge remain?

This is where you introduce your work:

Although giant strides have been made in recent years in the field of ..., there remains an open question as to ...The work described in the following chapters attempts to ...

7. Tying it up and introducing the next chapter

Your introductory chapter needs a conclusion, but it also needs to set up a sense of anticipation. You want the examiner to want to read the rest of your thesis (or at least the next chapter).So it's good to summarise the general principles you have just introduced, state a problem or question that needs an answer (and why it matters in relation to the general aims of your research field), and give a quick hint of how the next chapter will help to answer that question.

If man-made nanostructures are to follow a similar path [to nature], exploiting guided self-assembly to rapidly form functional structures, we must study both the physics of structure formation at the nanoscale and the influence of structure on function, specifically optical and electronic properties.Scanning probe techniques provide a versatile means of characterisation of these structures.Specifically, scanning near-field optical microscopy (SNOM)provides a means of optical characterisation with resolutions beyond the classical diffraction limit, in parallel with topographic information. These techniques, along with synchrotron based spectroscopy to probe deeper into theelectronic properties of nanostructured assemblies, will be discussed in the following chapters.

Does this structure work?

My examiner wrote in his report that the first chapter of my thesis was one of the best introductions to the subject he had ever read, including those published in the literature.

I was never a particularly good physicist, compared to some of the people I have worked with. But first impressions count, and introductions matter.