diff --git a/src/java/org/apache/poi/hssf/model/Model.java b/src/java/org/apache/poi/hssf/model/Model.java
new file mode 100644
index 0000000000..1b61d2dc3f
--- /dev/null
+++ b/src/java/org/apache/poi/hssf/model/Model.java
@@ -0,0 +1,11 @@
+package org.apache.poi.hssf.model;
+
+/**
+ * enclosing_type describe the purpose here
+ * 
+ * @author Andrew C. Oliver androliv@cisco.com
+ */
+public interface Model
+{
+
+}
diff --git a/src/java/org/apache/poi/hssf/model/Sheet.java b/src/java/org/apache/poi/hssf/model/Sheet.java
index 6e7abd01a8..1d8995aebd 100644
--- a/src/java/org/apache/poi/hssf/model/Sheet.java
+++ b/src/java/org/apache/poi/hssf/model/Sheet.java
@@ -87,8 +87,7 @@ import org.apache.poi.hssf.record
  * @version 1.0-pre
  */
 
-public class Sheet
-    extends java.lang.Object
+public class Sheet implements Model
 {
     public static final short   LeftMargin = 0;
     public static final short   RightMargin = 1;
diff --git a/src/java/org/apache/poi/hssf/model/Workbook.java b/src/java/org/apache/poi/hssf/model/Workbook.java
index e7deae3dce..4d71c35d72 100644
--- a/src/java/org/apache/poi/hssf/model/Workbook.java
+++ b/src/java/org/apache/poi/hssf/model/Workbook.java
@@ -92,7 +92,7 @@ import org.apache.poi.hssf.util.HSSFColor;
  * @version 1.0-pre
  */
 
-public class Workbook {
+public class Workbook implements Model {
     private static final int   DEBUG       = POILogger.DEBUG;
 
 //    public static Workbook currentBook = null;