diff --git a/common/hostreqs.xsl b/common/hostreqs.xsl
new file mode 100644
index 0000000..285d354
--- /dev/null
+++ b/common/hostreqs.xsl
@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+
+<!-- $Id:$ -->
+<!-- Extracts minimal versions from LFS book host requirements,
+     and generates a script containing statements of the
+     form MIN_prog_VERSION=xx.yy.zz.
+-->
+
+<xsl:stylesheet
+      xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+      version="1.0">
+
+  <xsl:output method="text"/>
+
+  <xsl:template match="/sect1">
+    <xsl:apply-templates select=".//listitem//emphasis"/>
+  </xsl:template>
+
+  <xsl:template match="emphasis">
+    <xsl:text>local MIN_</xsl:text>
+    <xsl:choose>
+      <xsl:when test="contains(string(),' ')">
+        <xsl:value-of select=
+           "substring-before(substring-after(normalize-space(string()),
+                                             ' '),
+                             '-')"/>
+      </xsl:when>
+      <xsl:otherwise>
+        <xsl:value-of select="substring-before(string(),'-')"/>
+      </xsl:otherwise>
+    </xsl:choose>
+    <xsl:text>_VER=</xsl:text>
+    <xsl:value-of select="substring-after(string(),'-')"/>
+    <xsl:text>
+</xsl:text>
+  </xsl:template>
+</xsl:stylesheet>
diff --git a/common/libs/func_book_parser b/common/libs/func_book_parser
index f1858d2..1b9582c 100644
--- a/common/libs/func_book_parser
+++ b/common/libs/func_book_parser
@@ -25,36 +25,17 @@ get_book() {                 #
     # Grab a fresh book if it's missing, otherwise, update it from the
     # repo. If we've already extracted the commands, move on to getting the
     # sources.
-    if [ -d ${PROGNAME}-$LFSVRS ] ; then
-      cd ${PROGNAME}-$LFSVRS
-      if LC_ALL=C svn up | grep -q At && \
-         test -d $JHALFSDIR/${PROGNAME}-commands && \
-         test -f $JHALFSDIR/pkg_tarball_list ; then
-        # Set the canonical book version
-        echo -ne "done\n"
-        cd $JHALFSDIR
-        case $PROGNAME in
-          clfs | clfs2 | clfs3 )
-            VERSION=$(xmllint --noent $BOOK/prologue/$ARCH/bookinfo.xml 2>/dev/null | grep subtitle | sed -e 's/^.*ion //'  -e 's/<\/.*//') ;;
-          *)
-            VERSION=$(xmllint --noent $BOOK/prologue/bookinfo.xml 2>/dev/null | grep subtitle | sed -e 's/^.*ion //'  -e 's/<\/.*//')  ;;
-        esac
-        get_sources
-      else
-        echo -ne "done\n"
-        extract_commands
-      fi
-    else
+    if ! [ -d ${PROGNAME}-$LFSVRS ] || ! [ -d ${PROGNAME}-$LFSVRS/.svn ]; then
       svn co $SVN/${svn_root}/${TREE} ${PROGNAME}-$LFSVRS >>$LOGDIR/$LOG 2>&1
-      echo -ne "done\n"
-      extract_commands
+    else
+      cd ${PROGNAME}-$LFSVRS
+      svn up >>$LOGDIR/$LOG 2>&1
     fi
+    echo -ne "done\n"
 
   else
     echo -ne "Using $BOOK as book's sources ...\n"
-    extract_commands
   fi
-  echo -ne " Document version ${L_arrow}${BOLD}${VERSION}${R_arrow}\n"
 }
 
 #----------------------------#
diff --git a/common/libs/func_check_version.sh b/common/libs/func_check_version.sh
index f13f936..024a1d1 100644
--- a/common/libs/func_check_version.sh
+++ b/common/libs/func_check_version.sh
@@ -22,7 +22,7 @@ inline_doc
 
   declare -i major minor revision change
   declare -i ref_major ref_minor ref_revision ref_change
-  declare -r spaceSTR="         "
+  declare -r spaceSTR="                   "
 
   shopt -s extglob	#needed for ${x##*(0)} below
 
@@ -65,13 +65,19 @@ inline_doc
   major=${1##*(0)}; minor=${2##*(0)}; revision=${3##*(0)}
   #
   # Compare against minimum acceptable version..
-  (( major > ref_major )) && echo " ${spaceSTR:${#tst_version}}${GREEN}OK${OFF}" && return
+  (( major > ref_major )) &&
+    echo " ${spaceSTR:${#tst_version}}${GREEN}OK${OFF} (Min version: ${ref_version})" &&
+    return
   (( major < ref_major )) && write_error_and_die
     # major=ref_major
   (( minor < ref_minor )) && write_error_and_die
-  (( minor > ref_minor )) && echo " ${spaceSTR:${#tst_version}}${GREEN}OK${OFF}" && return
+  (( minor > ref_minor )) &&
+    echo " ${spaceSTR:${#tst_version}}${GREEN}OK${OFF} (Min version: ${ref_version})" &&
+    return
     # minor=ref_minor
-  (( revision >= ref_revision )) && echo " ${spaceSTR:${#tst_version}}${GREEN}OK${OFF}" && return
+  (( revision >= ref_revision )) &&
+    echo " ${spaceSTR:${#tst_version}}${GREEN}OK${OFF} (Min version: ${ref_version})" &&
+    return
 
   # oops.. write error msg and die
   write_error_and_die
@@ -82,39 +88,41 @@ inline_doc
 check_prerequisites() {      #
 #----------------------------#
 
+  # Maybe we should check xsltproc first?
+  eval $(xsltproc $COMMON_DIR/hostreqs.xsl $BOOK/prologue/hostreqs.xml)
   # Avoid translation of version strings
   local LC_ALL=C
   export LC_ALL
 
   # LFS/HLFS/CLFS prerequisites
-  check_version "2.6.25"  "`uname -r`"          "KERNEL"
-  check_version "3.2"     "$BASH_VERSION"       "BASH"
-  check_version "4.1.2"   "`gcc -dumpversion`"  "GCC"
-  check_version "4.1.2"   "`g++ -dumpversion`"  "G++"
-  check_version "2.5.1"   "$(ldd --version  | head -n1 | awk '{print $NF}')"        "GLIBC"
-  check_version "2.17"    "$(ld --version  | head -n1 | awk '{print $NF}')"    "BINUTILS"
-  check_version "1.18"    "$(tar --version | head -n1 | cut -d" " -f4)"        "TAR"
+  check_version "$MIN_Kernel_VER"    "`uname -r`"          "KERNEL"
+  check_version "$MIN_Bash_VER"      "$BASH_VERSION"       "BASH"
+  check_version "$MIN_GCC_VER"       "`gcc -dumpversion`"  "GCC"
+  check_version "$MIN_GCC_VER"       "`g++ -dumpversion`"  "G++"
+  check_version "$MIN_Glibc_VER"     "$(ldd --version  | head -n1 | awk '{print $NF}')"   "GLIBC"
+  check_version "$MIN_Binutils_VER"  "$(ld --version  | head -n1 | awk '{print $NF}')"    "BINUTILS"
+  check_version "$MIN_Tar_VER"       "$(tar --version | head -n1 | cut -d" " -f4)"        "TAR"
   bzip2Ver="$(bzip2 --version 2>&1 < /dev/null | head -n1 | cut -d" " -f8)"
-  check_version "1.0.4"   "${bzip2Ver%%,*}"                                    "BZIP2"
-  check_version "2.3"     "$(bison --version | head -n1 | cut -d" " -f4)"      "BISON"
-  check_version "6.9"     "$(chown --version | head -n1 | cut -d")" -f2)"      "COREUTILS"
-  check_version "2.8.1"   "$(diff --version  | head -n1 | cut -d" " -f4)"      "DIFF"
-  check_version "4.2.31"  "$(find --version  | head -n1 | cut -d" " -f4)"      "FIND"
-  check_version "3.1.5"   "$(gawk --version  | head -n1 | cut -d" " -f3)"      "GAWK"
-  check_version "2.5.1a"  "$(grep --version  | head -n1 | awk '{print $NF}')"  "GREP"
-  check_version "1.3.12"  "$(gzip --version 2>&1 | head -n1 | cut -d" " -f2)"  "GZIP"
-  check_version "1.4.10"  "$(m4 --version 2>&1 | head -n1 | awk '{print $NF}')" "M4"
-  check_version "3.81"    "$(make --version  | head -n1 | cut -d " " -f3 | cut -c1-4)"  "MAKE"
-  check_version "2.5.4"   "$(patch --version | head -n1 | sed 's/.*patch //')"      "PATCH"
-  check_version "5.8.8"   "$(perl -V:version | cut -f2 -d\')"                  "PERL"
-  check_version "4.1.5"   "$(sed --version   | head -n1 | cut -d" " -f4)"      "SED"
-  check_version "4.9"	  "$(makeinfo --version | head -n1 | awk '{ print$NF }')" "TEXINFO"
-  check_version "5.0.0"   "$(xz --version | head -n1 | cut -d" " -f4)"         "XZ"
+  check_version "$MIN_Bzip2_VER"     "${bzip2Ver%%,*}"     "BZIP2"
+  check_version "$MIN_Bison_VER"     "$(bison --version | head -n1 | cut -d" " -f4)"      "BISON"
+  check_version "$MIN_Coreutils_VER" "$(chown --version | head -n1 | cut -d")" -f2)"      "COREUTILS"
+  check_version "$MIN_Diffutils_VER" "$(diff --version  | head -n1 | cut -d" " -f4)"      "DIFF"
+  check_version "$MIN_Findutils_VER" "$(find --version  | head -n1 | cut -d" " -f4)"      "FIND"
+  check_version "$MIN_Gawk_VER"      "$(gawk --version  | head -n1 | cut -d" " -f3)"      "GAWK"
+  check_version "$MIN_Grep_VER"      "$(grep --version  | head -n1 | awk '{print $NF}')"  "GREP"
+  check_version "$MIN_Gzip_VER"      "$(gzip --version 2>&1 | head -n1 | cut -d" " -f2)"  "GZIP"
+  check_version "$MIN_M4_VER"        "$(m4 --version 2>&1 | head -n1 | awk '{print $NF}')" "M4"
+  check_version "$MIN_Make_VER"      "$(make --version  | head -n1 | cut -d " " -f3 | cut -c1-4)" "MAKE"
+  check_version "$MIN_Patch_VER"     "$(patch --version | head -n1 | sed 's/.*patch //')" "PATCH"
+  check_version "$MIN_Perl_VER"      "$(perl -V:version | cut -f2 -d\')"                  "PERL"
+  check_version "$MIN_Sed_VER"       "$(sed --version   | head -n1 | cut -d" " -f4)"      "SED"
+  check_version "$MIN_Texinfo_VER"   "$(makeinfo --version | head -n1 | awk '{ print$NF }')" "TEXINFO"
+  check_version "$MIN_Xz_VER"        "$(xz --version | head -n1 | cut -d" " -f4)"         "XZ"
   # Check for minimum sudo version
   SUDO_LOC="$(whereis -b sudo | cut -d" " -f2)"
   if [ -x $SUDO_LOC ]; then
     sudoVer="$(sudo -V | head -n1 | cut -d" " -f3)"
-    check_version "1.6.8"  "${sudoVer}"      "SUDO"
+    check_version "1.7.0"  "${sudoVer}"      "SUDO"
   else
     echo "${nl_}\"${RED}sudo${OFF}\" ${BOLD}must be installed on your system for jhalfs to run"
     exit 1
diff --git a/jhalfs b/jhalfs
index 5f18b6e..0536c84 100755
--- a/jhalfs
+++ b/jhalfs
@@ -187,7 +187,7 @@ case $BRANCH_ID in
 esac
 
 # Set the document location...
-BOOK=${BOOK:=$PROGNAME-$LFSVRS}
+BOOK=${BOOK:=$JHALFSDIR/$PROGNAME-$LFSVRS}
 
 # blfs-tool envars
 BLFS_TOOL=${BLFS_TOOL:-n}
@@ -322,10 +322,6 @@ source $COMMON_DIR/libs/func_custom_pkgs
 ###          MAIN               ###
 ###################################
 
-# Check for build prerequisites.
-echo
-  check_prerequisites
-echo "${SD_BORDER}${nl_}"
 
 validate_config
 echo "${SD_BORDER}${nl_}"
@@ -461,7 +457,9 @@ if [[ "$REBUILD_MAKEFILE" = "n" ]] ; then
   fi
   #
 
+# Download or updates the book source
   get_book
+  extract_commands
   echo "${SD_BORDER}${nl_}"
 
   # Get the BLFS book, if requested.
@@ -495,4 +493,10 @@ build_Makefile
 
 echo "${SD_BORDER}${nl_}"
 
+# Check for build prerequisites.
+  echo
+  cd $CWD
+  check_prerequisites
+  echo "${SD_BORDER}${nl_}"
+# All is well, run the build (if requested)
 run_make