diff --git a/README.md b/README.md
index f5772ee..bd73d8b 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,59 @@
 # ivy
-IVy is a research tool intended to allow interactive development of protocols and their proofs of correctness and to provide a platform for developing and experimenting with automated proof techniques. In particular, IVy provides interactive visualization of automated proofs, and supports a use model in which the human protocol designer and the automated tool interact to expose errors and prove correctness.
+
+IVy is a research tool intended to allow interactive development of
+protocols and their proofs of correctness and to provide a platform
+for developing and experimenting with automated proof techniques. In
+particular, IVy provides interactive visualization of automated
+proofs, and supports a use model in which the human protocol designer
+and the automated tool interact to expose errors and prove
+correctness.
+
+## prerequisites
+
+### python 2.7
+
+Get it from [here](https://www.python.org/downloads) or as part of
+your Linux distribution.
+
+### Z3
+
+Following the instructions [here](https://github.com/Z3Prover/z3) to
+install Z3. Set the environment variable Z3DIR to the prefix at which
+you installed Z3. By defult this is /usr/local, in which case:
+
+    $ export Z3DIR = /usr/local
+
+### tcldot
+
+This is needed to run the Tcl/Tk-based user interface. You do not need
+this to use the browser-based user interface or the command-line
+interface. On Ubuntu, install it like this:
+
+    $ sudo apt-get install libgv-tcl
+
+## install
+
+Get the source like this:
+
+    $ git clone https://github.com/Microsoft/ivy.git
+
+Set the environment variable IVYDIR to point to the root of Ivy's
+source tree, like this:
+
+    $ cd ivy
+    $ export IVYDIR=`pwd`
+
+Add Ivy's bin directory to your path, like this:
+
+    $ export PATH=`pwd`/bin:$PATH
+
+## run
+
+Run Ivy on an example, using the Tcl/Tk user interface:
+
+    $ cd examples/ivy
+    $ ivy client_server.ivy
+
+
+
+
diff --git a/bin/ivy b/bin/ivy
index 6f65b03..9cc5c1e 100755
--- a/bin/ivy
+++ b/bin/ivy
@@ -1,8 +1,5 @@
 #/bin/sh
 
-Z3DIR=$HOME/projects/z3/release
-IVYDIR=$HOME/projects/ivy
-
 export PYTHONPATH=$Z3DIR:$IVYDIR/src/ivy:$IVYDIR/ivy
 
 python $IVYDIR/src/ivy/ivy.py $@