diff --git a/src/preface/acknowledgements.adoc b/src/preface/acknowledgements.adoc
index 82165a5f..4e13f321 100644
--- a/src/preface/acknowledgements.adoc
+++ b/src/preface/acknowledgements.adoc
@@ -14,6 +14,7 @@ Endres, Johannes +
 Gühring Philipp +
 Grigg, Ian +
 Haslinger, Gunnar +
+Horenbeck, Maarten +
 Huebl, Axel +
 Knecht, Pascal +
 Koetter, Patrick Ben +