To make a bootable Slackware install CD, get into the top level Slackware
directory (The one with ChangeLog.txt in it) and issue a command like this
to build the ISO image in /tmp:

mkisofs -o /tmp/slackware.iso \
-R -J -V "Slackware Install" \
-x ./bootdisks \
-x ./extra \
-x ./slackware/gnome \
-x ./pasture \
-x ./rootdisks \
-x ./source \
-x ./zipslack \
-hide-rr-moved \
-v -d -N -no-emul-boot -boot-load-size 4 -boot-info-table \
-sort isolinux/iso.sort \
-b isolinux/isolinux.bin \
-c isolinux/isolinux.boot \
-A "Slackware Install CD" . 

Then use 'cdrecord' to burn it.  (See 'man cdrecord')

Notice that to fit the install image on one CD, you must exclude GNOME:

-x ./slackware/gnome \

or exclude KDE:

-x ./slackware/kde \
-x ./slackware/kdei \

or, leave them both off:

-x ./slackware/gnome \
-x ./slackware/kde \
-x ./slackware/kdei \

or, leave off the KDEI series (KDE translations):

-x ./slackware/kdei \

You decide. :-)

----
notes:
   The isolinux/isolinux.boot file will be created on the CD;  it's not
   supposed to be in the source tree.  I mention this only because so many
   people reported the "missing" isolinux/isolinux.boot file as a bug.

  I don't know how to create a bootable Slackware ISO on operating systems
  other than Linux, but it should be easy to burn the Linux-created ISO with
  most CD burning software on any operating system.

  UPDATE:  I've now been informed that there's a Windows version of mkisofs
  available from ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/alpha if you want
  to try to make the ISO image under Windows.  I haven't tried this.

  Techincally the --boot-load-size should be a lot bigger, like 20 or so
  in order to hold the isolinux.bin boot block.  However, setting it to
  4 causes it to load on more BIOSes.  I don't know why, but I've had so
  many people report this to me that I'm inclined to believe it.  But, if
  the resulting discs don't boot in your machine and you find that using
  a more correct value here fixes it, please let me know!  If it's going
  to be broken for some BIOSes either way, I'd rather be correct.