diff --git a/reference/win32service/constants.xml b/reference/win32service/constants.xml
index b8d8f0cd9f..76954e9e9c 100644
--- a/reference/win32service/constants.xml
+++ b/reference/win32service/constants.xml
@@ -543,6 +543,79 @@
+
+ Win32 Base Priority Classes
+
+
+
+ Constant
+ Value
+ Description
+
+
+
+
+
+ WIN32_ABOVE_NORMAL_PRIORITY_CLASS
+ 0x00008000
+
+ Process that has priority above WIN32_NORMAL_PRIORITY_CLASS but below
+ WIN32_HIGH_PRIORITY_CLASS.
+
+
+
+ WIN32_BELOW_NORMAL_PRIORITY_CLASS
+ 0x00004000
+
+ Process that has priority above WIN32_IDLE_PRIORITY_CLASS but below
+ WIN32_NORMAL_PRIORITY_CLASS.
+
+
+
+ WIN32_HIGH_PRIORITY_CLASS
+ 0x00000080
+
+ Process that performs time-critical tasks that must be executed
+ immediately. The threads of the process preempt the threads of normal or
+ idle priority class processes. An example is the Task List, which must
+ respond quickly when called by the user, regardless of the load on the
+ operating system. Use extreme care when using the high-priority class,
+ because a high-priority class application can use nearly all available
+ CPU time.
+
+
+
+ WIN32_IDLE_PRIORITY_CLASS
+ 0x00000040
+
+ Process whose threads run only when the system is idle. The threads of the
+ process are preempted by the threads of any process running in a higher
+ priority class. An example is a screen saver. The idle-priority class is
+ inherited by child processes.
+
+
+
+ WIN32_NORMAL_PRIORITY_CLASS
+ 0x00000020
+
+ Process with no special scheduling needs.
+
+
+
+ WIN32_REALTIME_PRIORITY_CLASS
+ 0x00000100
+
+ Process that has the highest possible priority. The threads of the
+ process preempt the threads of all other processes, including operating
+ system processes performing important tasks. For example, a real-time
+ process that executes for more than a very brief interval can cause disk
+ caches not to flush or cause the mouse to be unresponsive.
+
+
+
+
+
+