diff --git a/Source/cmIfCommand.h b/Source/cmIfCommand.h
index 107a8923b..7c4baba4e 100644
--- a/Source/cmIfCommand.h
+++ b/Source/cmIfCommand.h
@@ -125,10 +125,13 @@ public:
       "True if the constant is 1, ON, YES, TRUE, Y, or a non-zero number.  "
       "False if the constant is 0, OFF, NO, FALSE, N, IGNORE, \"\", "
       "or ends in the suffix '-NOTFOUND'.  "
-      "Named boolean constants are case-insensitive."
+      "Named boolean constants are case-insensitive.  "
+      "If the argument is not one of these constants, "
+      "it is treated as a variable:"
       "\n"
       "  if(<variable>)\n"
-      "True if the variable's value is not a false constant."
+      "True if the variable is defined to a value that is not a false "
+      "constant.  False otherwise.  "
       "\n"
       "  if(NOT <expression>)\n"
       "True if the expression is not true."
@@ -199,38 +202,26 @@ public:
       "that contains them."
       "\n"
 
-      "The if statement was written fairly early in CMake's history "
-      "and it has some convenience features that are worth covering. "
-      "The if statement reduces operations until there is "
-      "a single remaining value, at that point if the case "
-      "insensitive value is: ON, 1, YES, TRUE, Y it returns true, if "
-      "it is OFF, 0, NO, FALSE, N, NOTFOUND, *-NOTFOUND, IGNORE it "
-      "will return false. \n"
-
-      "This is fairly reasonable. The convenience feature that sometimes "
-      "throws new authors is how CMake handles values that do not "
-      "match the true or false list. Those values are treated as "
-      "variables and are dereferenced even though they do not have "
-      "the required ${} syntax. This means that if you write\n"
-
-      "  if (boobah)\n"
-
-      "CMake will treat it as if you wrote \n"
-
-      "  if (${boobah})\n"
-
-      "likewise if you write \n"
-
-      "  if (fubar AND sol)\n"
-
-      "CMake will conveniently treat it as \n"
-
-      "  if (\"${fubar}\" AND \"${sol}\")\n"
-
-      "The later is really the correct way to write it, but the "
-      "former will work as well. Only some operations in the if "
-      "statement have this special handling of arguments. The "
-      "specific details follow: \n"
+      "The if command was written very early in CMake's history, predating "
+      "the ${} variable evaluation syntax, and for convenience evaluates "
+      "variables named by its arguments.  "
+      "Note that normal variable evaluation with ${} applies before the "
+      "if command even receives the arguments.  "
+      "Therefore code like\n"
+      "  set(var1 OFF)\n"
+      "  set(var2 \"var1\")\n"
+      "  if(${var2})\n"
+      "appears to the if command as\n"
+      "  if(var1)\n"
+      "and is evaluated according to the if(<variable>) case "
+      "documented above.  "
+      "The result is OFF which is false.  "
+      "However, if we remove the ${} from the example then the command sees\n"
+      "  if(var2)\n"
+      "which is true because var2 is defined to \"var1\" which is not "
+      "a false constant."
+      "\n"
+      "Automatic evaluation applies in the other cases as follows:\n"
 
       "1) The left hand argument to MATCHES is first checked to see "
       "if it is a defined variable, if so the variable's value is "