diff --git a/preface.asciidoc b/preface.asciidoc
index 94b7fcc..30ed467 100644
--- a/preface.asciidoc
+++ b/preface.asciidoc
@@ -9,7 +9,7 @@ This book is a collaboration between Andreas M. Antonopoulos, Olaoluwa Osuntokun
 [[intended_audience_sec]]
 === Intended Audience
 
-((("intended audience")))This book is mostly intended for *TBD*.
+((("intended audience")))This book is mostly intended for technical readers with an understanding of the fundamentals of Bitcoin and other open blockchains.
 
 [[conventinons_used_sec]]
 === Conventions Used in This Book