Try to clarify the names of lessons and modules.

training-slides/src/SUMMARY.md

@@ -1,6 +1,6 @@
-# Summary
+# Front Matter
 
-[Start Here](./start_here.md)
+[Introduction](./introduction.md)
 
 [Glossary](./glossary.md)
 
@@ -55,6 +55,9 @@ Topics that go beyond [Applied Rust](#applied-rust).
 * [The stdlib](./std-lib-tour.md)
 * [Using Cargo](./using-cargo.md)
 * [Using Types to encode State](./type-state.md)
+
+# Rust and Web Assembly
+
 * [WASM](./wasm.md)
 
 # No-Std Rust
@@ -96,7 +99,7 @@ Topics around [Ferrocene](https://ferrous-systems.com/ferrocene/), the qualified
 * [What is Ferrocene](./ferrocene-what-it-is.md)
 * [Installing and Using Ferrocene](./ferrocene-installing.md)
 
-# Rust for Decision Makers
+# Why Rust?
 
 * [What is Rust?](./what-is-rust.md)
 * [Safety, Performance, and Productivity](./safety-performance-productivity.md)

training-slides/src/introduction.md

@@ -0,0 +1,48 @@
+![Our cute logo!](images/logo_ferrous-systems_rgb.png)
+
+# Introduction
+
+This book contains our training material, divided up into individual slide decks. Each deck is a *lesson*. Those *lessons* combine to form a *module*, which is taught during a series of *sessions* within a *training*. See [the glossary](./glossary.md) for more details.
+
+This is the book version of our material. You can also see the lessons in slide form at <https://rust-training.ferrous-systems.com/latest/slides>.
+
+We have a standard grouping of *lessons* into *modules*, but this can be customised according to customer needs. The modules have dependencies - that is, pre-requisite knowledge required to get the most out of a particular module. The dependencies are shown in the following graphic.
+
+Most of our modules are available now (shown in blue), but some are still in development and will be available in the future (shown in grey).
+
+```mermaid
+---
+title: Ferrous Systems' Rust Training Modules
+config:
+  theme: base
+  themeVariables:
+    primaryColor: "#cdf"
+---
+graph TD;
+    Fundamentals(Rust Fundamentals)-->Applied(Applied Rust);
+    Applied-->Advanced(Advanced Rust);
+    Applied-->NoStd(No-Std Rust);
+    NoStd-->Ferrocene(Using Ferrocene);
+    Applied-->BareMetal(Bare-Metal Rust);
+    Applied-->Async(Async Rust);
+    Applied-->Wasm(Rust and WebAssembly);
+    BareMetal-->Embassy(Using Embassy);
+    Async-->Embassy;
+    WhyRust(Why Rust?);
+    WhyFerrocene(Why Ferrocene?);
+
+    classDef grey fill:#eee,stroke:#ccc;
+    class Async,Embassy grey
+```
+
+* **Why Rust?**: A (stand-alone) half-day tour of Rust for decision-makers, technical leads and managers.
+* **Why Ferrocene?**: A (stand-alone) 60 minute introduction to Ferrocene.
+* **Rust Fundamentals**: Covers the basics - types, writing functions, using iterators.
+* **Applied Rust**: Using Rust with Windows, macOS or Linux.
+* **Advanced Rust**: Deep-dives into specific topics.
+* **No-Std Rust**: Rust without the Standard Library.
+* **Bare-Metal Rust**: Rust on a microcontroller.
+* **Async Rust**: Futures, Polling, Tokio, and all that jazz.
+* **Rust and WebAssembly**: Using Rust to build WASM binaries, run in a sandbox or in an HTML page
+* **Ferrocene**: Working with our qualified toolchain.
+* **Using Embassy**: Async-Rust on a microcontroller.

training-slides/src/wasm.md

@@ -2,7 +2,7 @@
 
 ## What?
 
-WebAssembly(WASM) enables running Rust (among others) in a sandbox environment, including the browser.
+WebAssembly (WASM) enables running Rust (among others) in a sandbox environment, including the browser.
 
 WebAssembly is supported as a _compile target_.