diff --git a/RETRO-Book.md b/RETRO-Book.md
index bfe693d..f6932c0 100644
--- a/RETRO-Book.md
+++ b/RETRO-Book.md
@@ -20,11 +20,14 @@ of RETRO and how it works.
 
 # Building RETRO on BSD
 
+RETRO is well supported on BSD (FreeBSD, NetBSD, OpenBSD)
+systems. It should build on a base install of any of these
+without issue.
+
 ## Requirements
 
-- c compiler (tested: clang, tcc, gcc)
+- c compiler
 - make
-- standard unix shell
 
 ## Process
 
@@ -42,15 +45,18 @@ In the `bin/` directory:
     retro-muri
     retro-extend
     retro-embedimage
-
+    retro-describe
 
 # Building RETRO on Linux
 
+Building on Linux is pretty easy. You'll need to make sure
+you have a C compiler, headers, and make.
+
 ## Requirements
 
 - c compiler (tested: clang, tcc, gcc)
+- development headers
 - make
-- standard unix shell
 
 ## Process
 
@@ -68,15 +74,17 @@ In the `bin/` directory:
     retro-muri
     retro-extend
     retro-embedimage
-
+    retro-describe
 
 # Building RETRO on macOS
 
+To build on macOS, you will need the command line tools from
+Xcode. Install these and you should be able to build and use
+RETRO.
+
 ## Requirements
 
-- c compiler (tested: clang, tcc, gcc)
-- make
-- standard unix shell
+- command line tools from Xcode
 
 ## Process
 
diff --git a/book/Building-BSD b/book/Building-BSD
index e6733c2..95e1c5c 100644
--- a/book/Building-BSD
+++ b/book/Building-BSD
@@ -1,10 +1,13 @@
 # Building RETRO on BSD
 
+RETRO is well supported on BSD (FreeBSD, NetBSD, OpenBSD)
+systems. It should build on a base install of any of these
+without issue.
+
 ## Requirements
 
-- c compiler (tested: clang, tcc, gcc)
+- c compiler
 - make
-- standard unix shell
 
 ## Process
 
@@ -22,4 +25,4 @@ In the `bin/` directory:
     retro-muri
     retro-extend
     retro-embedimage
-
+    retro-describe
diff --git a/book/Building-Linux b/book/Building-Linux
index 86fb7bd..ed2b4dc 100644
--- a/book/Building-Linux
+++ b/book/Building-Linux
@@ -1,10 +1,13 @@
 # Building RETRO on Linux
 
+Building on Linux is pretty easy. You'll need to make sure
+you have a C compiler, headers, and make.
+
 ## Requirements
 
 - c compiler (tested: clang, tcc, gcc)
+- development headers
 - make
-- standard unix shell
 
 ## Process
 
@@ -22,4 +25,4 @@ In the `bin/` directory:
     retro-muri
     retro-extend
     retro-embedimage
-
+    retro-describe
diff --git a/book/Building-macOS b/book/Building-macOS
index b85be8f..f325e46 100644
--- a/book/Building-macOS
+++ b/book/Building-macOS
@@ -1,10 +1,12 @@
 # Building RETRO on macOS
 
+To build on macOS, you will need the command line tools from
+Xcode. Install these and you should be able to build and use
+RETRO.
+
 ## Requirements
 
-- c compiler (tested: clang, tcc, gcc)
-- make
-- standard unix shell
+- command line tools from Xcode
 
 ## Process