diff --git a/MdePkg/Include/Pi/PiFirmwareFile.h b/MdePkg/Include/Pi/PiFirmwareFile.h
index febebe7314..39c4def36d 100644
--- a/MdePkg/Include/Pi/PiFirmwareFile.h
+++ b/MdePkg/Include/Pi/PiFirmwareFile.h
@@ -156,7 +156,7 @@ typedef struct {
 typedef EFI_COMMON_SECTION_HEADER EFI_DXE_DEPEX_SECTION;
 
 ///
-/// Leaf section witch contains a PI FV.
+/// Leaf section which contains a PI FV.
 /// 
 typedef EFI_COMMON_SECTION_HEADER EFI_FIRMWARE_VOLUME_IMAGE_SECTION;
 
@@ -220,7 +220,7 @@ typedef struct {
 
 ///
 /// Leaf section which contains a numeric build number and
-/// an optional unicode string that represent the file revision. 
+/// an optional unicode string that represents the file revision. 
 /// 
 typedef struct {
   EFI_COMMON_SECTION_HEADER   CommonHeader;
diff --git a/MdePkg/Include/Pi/PiMultiPhase.h b/MdePkg/Include/Pi/PiMultiPhase.h
index b49971f813..a88258e583 100644
--- a/MdePkg/Include/Pi/PiMultiPhase.h
+++ b/MdePkg/Include/Pi/PiMultiPhase.h
@@ -1,7 +1,7 @@
 /** @file
   Include file matches things in PI for multiple module types.
 
-  Copyright (c) 2006 - 2007, Intel Corporation                                                         
+  Copyright (c) 2006 - 2008, Intel Corporation                                                         
   All rights reserved. This program and the accompanying materials                          
   are licensed and made available under the terms and conditions of the BSD License         
   which accompanies this distribution.  The full text of the license may be found at        
@@ -93,7 +93,7 @@ typedef struct {
 
 
 //
-// Bit values for AuthenticationStatus
+// Bit values for Authentication Status
 //
 #define EFI_AUTH_STATUS_PLATFORM_OVERRIDE   0x01
 #define EFI_AUTH_STATUS_IMAGE_SIGNED        0x02
diff --git a/MdePkg/Include/Pi/PiPeiCis.h b/MdePkg/Include/Pi/PiPeiCis.h
index 34691a0851..5efa75e150 100644
--- a/MdePkg/Include/Pi/PiPeiCis.h
+++ b/MdePkg/Include/Pi/PiPeiCis.h
@@ -613,7 +613,8 @@ typedef struct {
 } EFI_FV_INFO;
 
 /**
-   
+  Returns information about the specified volume.
+  
   This function returns information about a specific firmware
   volume, including its name, type, attributes, starting address
   and size.
@@ -637,7 +638,8 @@ EFI_STATUS
   );
 
 /**
-   
+  Register a PEIM so that it will be shadowed and called again.
+  
   This service registers a file handle so that after memory is
   available, the PEIM will be re-loaded into permanent memory and
   re-initialized. The PEIM registered this way will always be
@@ -648,8 +650,8 @@ EFI_STATUS
   initialized after permanent memory is installed, even the first
   time.
 
-  @param FileHandle   PEIM's file handle. Must be the currently
-                      executing PEIM.
+  @param FileHandle             PEIM's file handle. Must be the currently
+                                executing PEIM.
   
   @retval EFI_SUCCESS           The PEIM was successfully registered for
                                 shadowing.
@@ -722,6 +724,7 @@ struct _EFI_PEI_SERVICES {
   EFI_PEI_SET_MEM             SetMem;
   //
   // Status Code
+  //
   EFI_PEI_REPORT_STATUS_CODE  ReportStatusCode;
   //
   // Reset
@@ -736,6 +739,7 @@ struct _EFI_PEI_SERVICES {
   EFI_PEI_PCI_CFG2_PPI        *PciCfg;
   //
   // Future Installed Services
+  //
   EFI_PEI_FFS_FIND_BY_NAME    FfsFindFileByName;
   EFI_PEI_FFS_GET_FILE_INFO   FfsGetFileInfo;
   EFI_PEI_FFS_GET_VOLUME_INFO FfsGetVolumeInfo;
@@ -809,6 +813,7 @@ typedef struct _EFI_SEC_PEI_HAND_OFF {
 
 
 /**
+  Entry point of PEI Foundation.
 
   This function is the entry point for the PEI Foundation, which
   allows the SEC phase to pass information about the stack,
@@ -826,8 +831,7 @@ typedef struct _EFI_SEC_PEI_HAND_OFF {
                         information about the PEI core's
                         operating environment, such as the size
                         and location of temporary RAM, the stack
-                        location and the BFV location. The type
-                        EFI_SEC_PEI_HAND_OFF is
+                        location and the BFV location.
 
   @param PpiList        Points to a list of one or more PPI
                         descriptors to be installed initially by