Add more some context for the README

👋🏻 to anyone who's seeing this get done just before Let's Do Digital

README.md

@@ -1,6 +1,19 @@
 # Emap
 
-A monorepo for all core Emap functions
+Experimental Medicine Application Platform (EMAP) produces a near real-time database 
+containing clinical data for research and dashboard development within UCLH. 
+
+This is a non-operational “mirror” of a subset of UCLH data (historical and live). 
+The underpinning aim is to ensure that no clinical data are corrupted or destroyed during the interaction 
+between the research process and the hospital’s systems and that the systems are not compromised 
+(for instance, if they are interrupted or slowed down by research enquiries).
+
+For more information about EMAP, please see the [docs](https://github.com/SAFEHR-data/emap/tree/main/docs)
+
+## Developer onboarding
+
+- How to [configure IntelliJ](docs/dev/intellij.md) to build emap and run tests.
+- [Onboarding](docs/dev/onboarding.md) gives details on how data items are processed and the test strategies used.
 
 # Setup
 
@@ -19,12 +32,6 @@ EMAP [your root emap directory]
 │   ├── [etc.]
 ```
 
-## Developer onboarding
-
-- How to [configure IntelliJ](docs/dev/intellij.md) to build emap and run tests.
-- [Onboarding](docs/dev/onboarding.md) gives details on how data items are processed and the test strategies used.
-
-
 # Monorepo migration
 
 How were [old repos migrated into this repo?](docs/dev/migration.md)