Highlights must be the superb swirling Dalek City sounds, the full TARDIS take-off and the various versions of the original "Who" theme tune, but there are countless other atmospheric tracks. Radiophonic Workshop "guardian" Mark Ayres has done a fantastic job in finding and restoring these cues to their present quality. There are also a few tantalizing segments of Dudley Simpson's early incidental music using the BBC's electronic organ and synthesizers.
Forget the repetitive and unimaginative sounds of Star Trek: The Next Money Grabbing Franchise, these are truly the most original and otherworldly special sounds you are likey to hear.
I highly recommend this release, and also its sequel, volume 2!