Yes Nige, the freehub body is missing (black part in pic:) http://www.sheldonbrown.com/images/freewheel-vs-k7.jpg
so it'll need a freehub, singlespeed cog in size of your choice, some spacers and a locknut. Then you'll have a singlespeed freewheel bike. There's no threaded part to spin on a track cog. Oh, and you'll need a spindle and some bearings!
Yes Nige, the freehub body is missing (black part in pic:)
http://www.sheldonbrown.com/images/freewheel-vs-k7.jpg
so it'll need a freehub, singlespeed cog in size of your choice, some spacers and a locknut. Then you'll have a singlespeed freewheel bike. There's no threaded part to spin on a track cog. Oh, and you'll need a spindle and some bearings!