diff --git a/src/UglyToad.PdfPig.DocumentLayoutAnalysis/ReadingOrderDetector/IReadingOrderDetector.cs b/src/UglyToad.PdfPig.DocumentLayoutAnalysis/ReadingOrderDetector/IReadingOrderDetector.cs
index 08f62d69..3d696ffc 100644
--- a/src/UglyToad.PdfPig.DocumentLayoutAnalysis/ReadingOrderDetector/IReadingOrderDetector.cs
+++ b/src/UglyToad.PdfPig.DocumentLayoutAnalysis/ReadingOrderDetector/IReadingOrderDetector.cs
@@ -4,6 +4,7 @@
 
     /// <summary>
     /// Reading order detector determines the page's blocks reading order.
+    /// <para>Note: Make sure you use <see cref="TextBlock.SetReadingOrder(int)"/> to set each <see cref="TextBlock"/> reading order when implementing <see cref="IReadingOrderDetector.Get(IReadOnlyList{TextBlock})"/>.</para>
     /// </summary>
     public interface IReadingOrderDetector
     {
diff --git a/src/UglyToad.PdfPig.DocumentLayoutAnalysis/TextBlock.cs b/src/UglyToad.PdfPig.DocumentLayoutAnalysis/TextBlock.cs
index ffba3a21..6e793104 100644
--- a/src/UglyToad.PdfPig.DocumentLayoutAnalysis/TextBlock.cs
+++ b/src/UglyToad.PdfPig.DocumentLayoutAnalysis/TextBlock.cs
@@ -67,7 +67,11 @@
             TextDirection = lines[0].TextDirection;
         }
 
-        internal void SetReadingOrder(int readingOrder)
+        /// <summary>
+        /// Sets the <see cref="TextBlock"/>'s reading order.
+        /// </summary>
+        /// <param name="readingOrder"></param>
+        public void SetReadingOrder(int readingOrder)
         {
             if (readingOrder < -1)
             {