diff --git a/.gitignore b/.gitignore
index 45b52f4..41dd58e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,7 @@
 sim-applet/test
 .sim-keys*
 sim-keys*
+docs/*.pdf
+docs/build
+docs/common
+docs/*.png
diff --git a/docs/Makefile b/docs/Makefile
new file mode 100644
index 0000000..815909e
--- /dev/null
+++ b/docs/Makefile
@@ -0,0 +1,8 @@
+OSMO_GSM_MANUALS_DIR := $(shell ./osmo-gsm-manuals-dir.sh)
+srcdir=$(CURDIR)
+
+ASCIIDOC = imsi-pseudo-spec.adoc
+ASCIIDOC_DEPS =
+include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.asciidoc.inc
+
+include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.common.inc
diff --git a/docs/imsi-pseudo-spec-docinfo.xml b/docs/imsi-pseudo-spec-docinfo.xml
new file mode 100644
index 0000000..de798c7
--- /dev/null
+++ b/docs/imsi-pseudo-spec-docinfo.xml
@@ -0,0 +1,46 @@
+<revhistory>
+  <revision>
+    <revnumber>1</revnumber>
+    <date>2020-04-03</date>
+    <authorinitials>OS</authorinitials>
+    <revremark>
+      Initial version.
+    </revremark>
+  </revision>
+ </revhistory>
+
+<authorgroup>
+  <author>
+    <firstname>Oliver</firstname>
+    <surname>Smith</surname>
+    <email>osmith@sysmocom.de</email>
+    <authorinitials>OS</authorinitials>
+    <affiliation>
+      <shortaffil>sysmocom</shortaffil>
+      <orgname>sysmocom - s.f.m.c. GmbH</orgname>
+      <jobtitle>Employee</jobtitle>
+    </affiliation>
+  </author>
+</authorgroup>
+
+<copyright>
+  <year>2020</year>
+  <holder>sysmocom - s.f.m.c. GmbH</holder>
+</copyright>
+
+<legalnotice>
+  <para>
+	Permission is granted to copy, distribute and/or modify this
+	document under the terms of the GNU Free Documentation License,
+	Version 1.3 or any later version published by the Free Software
+	Foundation; with no Invariant Sections, no Front-Cover Texts,
+	and no Back-Cover Texts.  A copy of the license is included in
+	the section entitled "GNU Free Documentation License".
+  </para>
+  <para>
+	The Asciidoc source code of this manual is linked at
+	<ulink url="https://osmocom.org/projects/imsi-pseudo/wiki">
+		https://osmocom.org/projects/imsi-pseudo/wiki
+	</ulink>
+  </para>
+</legalnotice>
diff --git a/docs/imsi-pseudo-spec.adoc b/docs/imsi-pseudo-spec.adoc
new file mode 100644
index 0000000..4cb365d
--- /dev/null
+++ b/docs/imsi-pseudo-spec.adoc
@@ -0,0 +1 @@
+= IMSI Pseudonymization
diff --git a/docs/osmo-gsm-manuals-dir.sh b/docs/osmo-gsm-manuals-dir.sh
new file mode 100755
index 0000000..d080bc7
--- /dev/null
+++ b/docs/osmo-gsm-manuals-dir.sh
@@ -0,0 +1,26 @@
+#!/bin/sh -e
+# Find OSMO_GSM_MANUALS_DIR and print it to stdout. Print where it was taken from to stderr.
+
+# Find it in env, pkg-conf and ../../osmo-gsm-manuals
+RET="$OSMO_GSM_MANUALS_DIR"
+if [ -n "$RET" ]; then
+	RET="$(realpath $RET)"
+	echo "OSMO_GSM_MANUALS_DIR: $RET (from env)" >&2
+else
+	RET="$(pkg-config osmo-gsm-manuals --variable=osmogsmmanualsdir 2>/dev/null || true)"
+	if [ -n "$RET" ]; then
+		echo "OSMO_GSM_MANUALS_DIR: $RET (from pkg-conf)" >&2
+	else
+		RET="$(realpath $(realpath $(dirname $0))/../../osmo-gsm-manuals)"
+		echo "OSMO_GSM_MANUALS_DIR: $RET (fallback)" >&2
+	fi
+fi
+
+# Print the result or error message
+if [ -d "$RET" ]; then
+	echo "$RET"
+else
+	echo "ERROR: OSMO_GSM_MANUALS_DIR does not exist!" >&2
+	echo "Install osmo-gsm-manuals or set OSMO_GSM_MANUALS_DIR." >&2
+	exit 1
+fi