diff --git a/winbuild/BUILD.WINDOWS.txt b/winbuild/BUILD.WINDOWS.txt
index 7d6b364e24..600f737469 100644
--- a/winbuild/BUILD.WINDOWS.txt
+++ b/winbuild/BUILD.WINDOWS.txt
@@ -76,3 +76,14 @@ where <options> is one or many of:
   GEN_PDB=<yes or no>          - Generate Program Database (debug symbols for release build)
   DEBUG=<yes or no>            - Debug builds
   MACHINE=<x86 or x64>         - Target architecture (default is x86)
+
+Static linking of Microsoft's C RunTime (CRT):
+==============================================
+If you are using mode=static nmake will create and link to the static build of
+libcurl but *not* the static CRT. If you must you can force nmake to link in
+the static CRT by passing RTLIBCFG=static. Typically you shouldn't use that
+option, and nmake will default to the DLL CRT. RTLIBCFG is rarely used and
+therefore rarely tested. When passing RTLIBCFG for a configuration that was
+already built but not with that option, or if the option was specified
+differently, you must destroy the build directory containing the configuration
+so that nmake can build it from scratch.