Merge pull request #56 from robmoss/overview/pitch

Briefly describe motivations for these materials

src/README.md

@@ -4,6 +4,37 @@ These materials aim to support
 early- and mid-career researchers (EMCRs) in the
 [SPECTRUM](https://www.spectrum.edu.au/) and [SPARK](https://www.spark.edu.au/) networks to develop their computing skills, and to make effective use of available tools[^tools] and infrastructure[^infra].
 
+## Motivation
+
+```admonish question
+Why dedicate time and effort to learning these skills?
+There are **many reasons!**
+```
+
+The overall aim of these materials is help you conduct code-driven research **more efficiently** and with **greater confidence**.
+
+Hopefully some of the following reasons resonate with you.
+
+- **Fearlessly modify your code**, knowing that your past work is never lost, by using [version control](./version-control/).
+
+- **Verify that your code behaves as expected**, and get notified when it doesn't, by [writing tests](./testing/).
+
+- **Ensure that your results won't change** when running on a different computer by "baking in" [reproducibility](./reproducibility/).
+
+- **Improve your coding skills**, and those of your colleagues, by working [collaboratively](./collaborating/) and making use of [peer code review](./collaborating/peer-code-review.md).
+
+- **Run your code quickly**, and without relying on your own laptop or computer, by using [high-performance computing](./high-performance-computing/).
+
+```admonish tip title="Foundations of effective research"
+A piece of code is often useful beyond a single project or study.
+
+By applying the above skills in your research, you will be able to easily reproduce past results, extend your code to address new questions and problems, and allow others to build on your code in their own research.
+
+**The benefits of good practices can continue to pay off long after the project is finished**.
+```
+
+## Structure
+
 These materials are divided into the following sections:
 
 1. Understanding [version control](./version-control/), which provides you with a complete and annotated history of your work, and with powerful ways to search and examine this history.