diff --git a/README.md b/README.md
index 4d1245d..819bf62 100644
--- a/README.md
+++ b/README.md
@@ -2,11 +2,12 @@
 
 This template allows you to get started in creating your own [sourcebook](https://en.wikipedia.org/wiki/Sourcebook) for a campaign setting or supplementary rulebook, based on the [System Reference Document](https://git.tonybark.com/sixam/dnd-5e-srd-markdown) (SRD).
 
-## Prerequisites
+## Recommendations
 
 - Any Markdown-supported text editor
 	- [Obsidian](https://obsidian.md/) or VSCode is recommended
-- [mdBook](https://rust-lang.github.io/mdBook/) (optional)
+- [mdBook](https://rust-lang.github.io/mdBook/)
+- [Harper](https://writewithharper.com/) spellcheck
 
 ## Declaimer