diff --git a/Photos-version-5-database.md b/Photos-version-5-database.md
index e216cba..5e24efa 100644
--- a/Photos-version-5-database.md
+++ b/Photos-version-5-database.md
@@ -47,6 +47,11 @@ If you change the sort order manually, the value of `Z_FOK_34ASSETS` of the phot
 
 See also the [discussion in #184](https://github.com/RhetTbull/osxphotos/issues/184)
 
+## Import Sessions
+
+Import sessions are stored in `ZGENERICALBUM` with 'ZKIND = 1506`.  When a photo is imported, the value ZGENERICASSET.ZIMPORTSESSION is set to the primary key of the corresponding import album in `ZGENERICALBUM`.
+
+
 **TODO** Document the following
 
 * [ ] Joining assets