typedef struct _PEB
{
     UCHAR InheritedAddressSpace;
     UCHAR ReadImageFileExecOptions;
     UCHAR BeingDebugged;
     UCHAR BitField;
     ULONG ImageUsesLargePages: 1;
     ULONG IsProtectedProcess: 1;
     ULONG IsLegacyProcess: 1;
     ULONG IsImageDynamicallyRelocated: 1;
     ULONG SpareBits: 4;
     PVOID Mutant;
     PVOID ImageBaseAddress;
     PPEB_LDR_DATA Ldr;
     PRTL_USER_PROCESS_PARAMETERS ProcessParameters;
     PVOID SubSystemData;
     PVOID ProcessHeap;
     PRTL_CRITICAL_SECTION FastPebLock;
     PVOID AtlThunkSListPtr;
     PVOID IFEOKey;
     ULONG CrossProcessFlags;
     ULONG ProcessInJob: 1;
     ULONG ProcessInitializing: 1;
     ULONG ReservedBits0: 30;
     union
     {
          PVOID KernelCallbackTable;
          PVOID UserSharedInfoPtr;
     };
     ULONG SystemReserved[1];
     ULONG SpareUlong;
     PPEB_FREE_BLOCK FreeList;
     ULONG TlsExpansionCounter;
     PVOID TlsBitmap;
     ULONG TlsBitmapBits[2];
     PVOID ReadOnlySharedMemoryBase;
     PVOID HotpatchInformation;
     VOID * * ReadOnlyStaticServerData;
     PVOID AnsiCodePageData;
     PVOID OemCodePageData;
     PVOID UnicodeCaseTableData;
     ULONG NumberOfProcessors;
     ULONG NtGlobalFlag;
     LARGE_INTEGER CriticalSectionTimeout;
     ULONG HeapSegmentReserve;
     ULONG HeapSegmentCommit;
     ULONG HeapDeCommitTotalFreeThreshold;
     ULONG HeapDeCommitFreeBlockThreshold;
     ULONG NumberOfHeaps;
     ULONG MaximumNumberOfHeaps;
     VOID * * ProcessHeaps;
     PVOID GdiSharedHandleTable;
     PVOID ProcessStarterHelper;
     ULONG GdiDCAttributeList;
     PRTL_CRITICAL_SECTION LoaderLock;
     ULONG OSMajorVersion;
     ULONG OSMinorVersion;
     WORD OSBuildNumber;
     WORD OSCSDVersion;
     ULONG OSPlatformId;
     ULONG ImageSubsystem;
     ULONG ImageSubsystemMajorVersion;
     ULONG ImageSubsystemMinorVersion;
     ULONG ImageProcessAffinityMask;
     ULONG GdiHandleBuffer[34];
     PVOID PostProcessInitRoutine;
     PVOID TlsExpansionBitmap;
     ULONG TlsExpansionBitmapBits[32];
     ULONG SessionId;
     ULARGE_INTEGER AppCompatFlags;
     ULARGE_INTEGER AppCompatFlagsUser;
     PVOID pShimData;
     PVOID AppCompatInfo;
     UNICODE_STRING CSDVersion;
     _ACTIVATION_CONTEXT_DATA * ActivationContextData;
     _ASSEMBLY_STORAGE_MAP * ProcessAssemblyStorageMap;
     _ACTIVATION_CONTEXT_DATA * SystemDefaultActivationContextData;
     _ASSEMBLY_STORAGE_MAP * SystemAssemblyStorageMap;
     ULONG MinimumStackCommit;
     _FLS_CALLBACK_INFO * FlsCallback;
     LIST_ENTRY FlsListHead;
     PVOID FlsBitmap;
     ULONG FlsBitmapBits[4];
     ULONG FlsHighIndex;
     PVOID WerRegistrationData;
     PVOID WerShipAssertPtr;
} PEB, *PPEB;

Windows Vista Kernel Structures