diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index e017f8a..3c257ee 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -27,6 +27,7 @@
   - [Requirements](./design/analysis/requirements.md)
 - [Development](./development/intro.md)
   - [Glossary](./development/glossary.md)
+  - [Decision Log](./development/decision_log.md)
   - [Release process](./development/release_process.md)
   - [Testing](./development/testing.md)
 - [Talks](./talks.md)
diff --git a/src/development/decision_log.md b/src/development/decision_log.md
new file mode 100644
index 0000000..d139c4c
--- /dev/null
+++ b/src/development/decision_log.md
@@ -0,0 +1,12 @@
+# Decision Log
+
+This document contains a log of decisions made during the development within the
+rustic ecosystem.
+
+## 2024-09-16: Naming Conventions for Types
+
+We will use the following naming conventions for the following types:
+
+- Singular: `Type`, exactly one value, e.g. `path: Path`
+- Plural: `Vec<Type>`, an array that may contain one or more values, e.g.
+  `paths: Vec<Path>`