diff --git a/applications/lazstats/docs/chm/LazStats.chm b/applications/lazstats/LazStats.chm
similarity index 99%
rename from applications/lazstats/docs/chm/LazStats.chm
rename to applications/lazstats/LazStats.chm
index 22ea2253a..5e1bc30fb 100644
Binary files a/applications/lazstats/docs/chm/LazStats.chm and b/applications/lazstats/LazStats.chm differ
diff --git a/applications/lazstats/source/forms/analysis/descriptive/boxplotunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/boxplotunit.lfm
index f3427f97a..765ca547b 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/boxplotunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/boxplotunit.lfm
@@ -3,6 +3,8 @@ object BoxPlotFrm: TBoxPlotFrm
   Height = 365
   Top = 119
   Width = 361
+  HelpType = htKeyword
+  HelpKeyword = 'BoxPlots.htm'
   AutoSize = True
   Caption = 'Box Plot'
   ClientHeight = 365
diff --git a/applications/lazstats/source/forms/analysis/descriptive/breakdownunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/breakdownunit.lfm
index db37affaf..caf157d31 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/breakdownunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/breakdownunit.lfm
@@ -3,6 +3,8 @@ object BreakDownFrm: TBreakDownFrm
   Height = 367
   Top = 248
   Width = 428
+  HelpType = htKeyword
+  HelpKeyword = 'Breakdown.htm'
   AutoSize = True
   Caption = 'Breakdown'
   ClientHeight = 367
diff --git a/applications/lazstats/source/forms/analysis/descriptive/bubbleplotunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/bubbleplotunit.lfm
index d6d7d8e44..f4645c129 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/bubbleplotunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/bubbleplotunit.lfm
@@ -3,6 +3,8 @@ object BubbleForm: TBubbleForm
   Height = 454
   Top = 253
   Width = 500
+  HelpType = htKeyword
+  HelpKeyword = 'RepeatedMeasuresBubblePlot.htm'
   AutoSize = True
   Caption = 'Repeated Measures Bubble Plot'
   ClientHeight = 454
diff --git a/applications/lazstats/source/forms/analysis/descriptive/comparedistunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/comparedistunit.lfm
index 6093a06ab..65644578a 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/comparedistunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/comparedistunit.lfm
@@ -3,6 +3,8 @@ object CompareDistFrm: TCompareDistFrm
   Height = 375
   Top = 227
   Width = 516
+  HelpType = htKeyword
+  HelpKeyword = 'ComparisonsWithTheoreticalDistri.htm'
   AutoSize = True
   Caption = 'Compare Cumulative Distributions'
   ClientHeight = 375
diff --git a/applications/lazstats/source/forms/analysis/descriptive/crosstabunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/crosstabunit.lfm
index 995f496c2..79998af64 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/crosstabunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/crosstabunit.lfm
@@ -3,6 +3,8 @@ object CrossTabFrm: TCrossTabFrm
   Height = 347
   Top = 230
   Width = 421
+  HelpType = htKeyword
+  HelpKeyword = 'Cross-tabulation.htm'
   AutoSize = True
   Caption = 'Cross Tabulation'
   ClientHeight = 347
diff --git a/applications/lazstats/source/forms/analysis/descriptive/descriptiveunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/descriptiveunit.lfm
index b9166b2da..2fddf9a49 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/descriptiveunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/descriptiveunit.lfm
@@ -3,6 +3,8 @@ object DescriptiveFrm: TDescriptiveFrm
   Height = 393
   Top = 226
   Width = 453
+  HelpType = htKeyword
+  HelpKeyword = 'DistributionStatistics.htm'
   AutoSize = True
   Caption = 'Descriptive Statistics'
   ClientHeight = 393
diff --git a/applications/lazstats/source/forms/analysis/descriptive/frequnit.lfm b/applications/lazstats/source/forms/analysis/descriptive/frequnit.lfm
index 21519c87a..a24bae3ec 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/frequnit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/frequnit.lfm
@@ -3,6 +3,8 @@ object FreqFrm: TFreqFrm
   Height = 388
   Top = 228
   Width = 502
+  HelpType = htKeyword
+  HelpKeyword = 'FrequencyAnalysis.htm'
   Caption = 'Frequency Distribution'
   ClientHeight = 388
   ClientWidth = 502
diff --git a/applications/lazstats/source/forms/analysis/descriptive/groupfrequnit.lfm b/applications/lazstats/source/forms/analysis/descriptive/groupfrequnit.lfm
index 9712c7273..67139234b 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/groupfrequnit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/groupfrequnit.lfm
@@ -3,6 +3,8 @@ object GroupFreqForm: TGroupFreqForm
   Height = 341
   Top = 233
   Width = 444
+  HelpType = htKeyword
+  HelpKeyword = 'GroupFrequencyHistograms.htm'
   AutoSize = True
   Caption = 'Group Frequency Analysis'
   ClientHeight = 341
diff --git a/applications/lazstats/source/forms/analysis/descriptive/multxvsyunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/multxvsyunit.lfm
index 4486ed661..0454193c1 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/multxvsyunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/multxvsyunit.lfm
@@ -3,6 +3,8 @@ object MultXvsYFrm: TMultXvsYFrm
   Height = 416
   Top = 216
   Width = 395
+  HelpType = htKeyword
+  HelpKeyword = 'MultipleGroupXVersusYPlot.htm'
   Anchors = [akLeft]
   AutoSize = True
   Caption = 'Multiple X Versus Y Plot'
diff --git a/applications/lazstats/source/forms/analysis/descriptive/normalityunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/normalityunit.lfm
index 2fb9153b5..c85b6fd0a 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/normalityunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/normalityunit.lfm
@@ -3,6 +3,8 @@ object NormalityFrm: TNormalityFrm
   Height = 396
   Top = 294
   Width = 402
+  HelpType = htKeyword
+  HelpKeyword = 'NormalityTests.htm'
   Caption = 'Normality Tests'
   ClientHeight = 396
   ClientWidth = 402
diff --git a/applications/lazstats/source/forms/analysis/descriptive/plotxyunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/plotxyunit.lfm
index c56c4762e..af878686e 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/plotxyunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/plotxyunit.lfm
@@ -3,6 +3,8 @@ object PlotXYFrm: TPlotXYFrm
   Height = 367
   Top = 262
   Width = 490
+  HelpType = htKeyword
+  HelpKeyword = 'XVersusYPlot.htm'
   AutoSize = True
   Caption = 'Plot X versus Y'
   ClientHeight = 367
diff --git a/applications/lazstats/source/forms/analysis/descriptive/resistancelineunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/resistancelineunit.lfm
index 9ba16eef9..4d3e52cd0 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/resistancelineunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/resistancelineunit.lfm
@@ -3,6 +3,8 @@ object ResistanceLineForm: TResistanceLineForm
   Height = 480
   Top = 301
   Width = 535
+  HelpType = htKeyword
+  HelpKeyword = 'ResistantLineforBivariateData.htm'
   Caption = 'Resistant Line for Bivariate Data'
   ClientHeight = 480
   ClientWidth = 535
diff --git a/applications/lazstats/source/forms/analysis/descriptive/rot3dunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/rot3dunit.lfm
index 603da14e2..460158ec4 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/rot3dunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/rot3dunit.lfm
@@ -3,6 +3,8 @@ object Rot3DFrm: TRot3DFrm
   Height = 527
   Top = 153
   Width = 710
+  HelpType = htKeyword
+  HelpKeyword = 'ThreeDimensionalRotation.htm'
   Caption = 'Three Dimension Rotation'
   ClientHeight = 527
   ClientWidth = 710
diff --git a/applications/lazstats/source/forms/analysis/descriptive/smoothdataunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/smoothdataunit.lfm
index e918549e4..f96606b2e 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/smoothdataunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/smoothdataunit.lfm
@@ -3,6 +3,8 @@ object DataSmoothingForm: TDataSmoothingForm
   Height = 388
   Top = 284
   Width = 372
+  HelpType = htKeyword
+  HelpKeyword = 'DataSmoothing.htm'
   AutoSize = True
   Caption = 'Smooth Data'
   ClientHeight = 388
diff --git a/applications/lazstats/source/forms/analysis/descriptive/stemleafunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/stemleafunit.lfm
index c18b699a7..e73f18329 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/stemleafunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/stemleafunit.lfm
@@ -3,6 +3,8 @@ object StemLeafFrm: TStemLeafFrm
   Height = 296
   Top = 257
   Width = 407
+  HelpType = htKeyword
+  HelpKeyword = 'StemandLeafPlot.htm'
   AutoSize = True
   Caption = 'Stem and Leaf Analysis'
   ClientHeight = 296
diff --git a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm
index 87d92a7ba..f652409fc 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm
@@ -3,6 +3,8 @@ object XvsMultYForm: TXvsMultYForm
   Height = 467
   Top = 117
   Width = 452
+  HelpType = htKeyword
+  HelpKeyword = 'PlotXVersusMultipleYValues.htm'
   Caption = 'X vs Multiple Y Plot'
   ClientHeight = 467
   ClientWidth = 452
diff --git a/applications/lazstats/source/forms/analysis/matrix_manipulation/matmanunit.lfm b/applications/lazstats/source/forms/analysis/matrix_manipulation/matmanunit.lfm
index 8bac64e0c..734fd2c9b 100644
--- a/applications/lazstats/source/forms/analysis/matrix_manipulation/matmanunit.lfm
+++ b/applications/lazstats/source/forms/analysis/matrix_manipulation/matmanunit.lfm
@@ -3,6 +3,8 @@ object MatManFrm: TMatManFrm
   Height = 575
   Top = 176
   Width = 943
+  HelpType = htKeyword
+  HelpKeyword = 'DistributionStatistics.htm'
   Caption = 'Matrix Manipulation'
   ClientHeight = 555
   ClientWidth = 943
diff --git a/applications/lazstats/source/forms/mainunit.pas b/applications/lazstats/source/forms/mainunit.pas
index 920b59541..ec7a75ff3 100644
--- a/applications/lazstats/source/forms/mainunit.pas
+++ b/applications/lazstats/source/forms/mainunit.pas
@@ -7,11 +7,18 @@ unit MainUnit;
 
 {$mode objfpc}{$H+}
 
+{$DEFINE USE_EXTERNAL_HELP_VIEWER}
+
 interface
 
 uses
   Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
   Menus, ExtCtrls, StdCtrls, Grids,
+ {$IFDEF USE_EXTERNAL_HELP_VIEWER}
+  {$IFDEF MSWINDOWS}
+  HtmlHelp,
+  {$ENDIF}
+ {$ENDIF}
   Globals, DataProcs, DictionaryUnit;
 
 type
@@ -424,6 +431,11 @@ type
     procedure XvsMultYClick(Sender: TObject);
   private
     { private declarations }
+   {$IFDEF USE_EXTERNAL_HELP_VIEWER}
+    {$IFDEF MSWINDOWS}
+    function HelpHandler(Command: Word; Data: PtrInt; var CallHelp: Boolean): Boolean;
+    {$ENDIF}
+   {$ENDIF}
     procedure Init;
   public
     { public declarations }
@@ -1280,9 +1292,15 @@ begin
   if OutputFrm = nil then
     Application.CreateForm(TOutputFrm, OutputFrm);
 
-(*  if OptionsFrm = nil then
-    Application.CreateForm(TOptionsFrm, OptionsFrm);
-    *)
+ {$IFDEF USE_EXTERNAL_HELP_VIEWER}
+  {$IFDEF MSWINDOWS}
+  Application.HelpFile := Application.Location + 'LazStats.chm';
+  if FileExists(Application.HelpFile) then
+    Application.OnHelp := @HelpHandler
+  else
+    Application.HelpFile := '';
+  {$ENDIF}
+ {$ENDIF}
 end;
 
 procedure TOS3MainFrm.DataGridKeyPress(Sender: TObject; var Key: char);
@@ -1564,6 +1582,25 @@ begin
   end;
 end;
 
+{$IFDEF USE_EXTERNAL_HELP_VIEWER}
+{$IFDEF MSWINDOWS}
+// Call HTML help (.chm file)
+// Is is expected that help topics are specified as HelpKeyword (HelpType = htContext).
+// Using numeric HelpContext values will crash the application.
+function TOS3MainFrm.HelpHandler(Command:word; Data:PtrInt;
+  var CallHelp:Boolean): Boolean;
+var
+  topic: UnicodeString;
+begin
+  topic := Application.HelpFile + '::/' + PChar(Data);
+  htmlhelp.HtmlHelpW(0, PWideChar(topic), HH_DISPLAY_TOPIC, 0);
+
+  // Don't call regular help
+  CallHelp := False;
+end;
+{$ENDIF}
+{$ENDIF}
+
 procedure TOS3MainFrm.Init;
 var
   i: integer;