Khorasan flour is an interesting ancient grain which has begun to become more widely known in the last few years. It's also known as Kamut, which is a trade marked version of the same grain. The trade mark itself is an attempt to make sure this grain is properly grown and looked after (the trade mark insists on the grain being bio dynamically grown - a worthy aim, but one wonders if the trademark holder may be making a shackle for their own back in the long run).
My understanding of the wheat family, from which all the grains commonly used to make bread come, is that there are two breeding aims which humans have worked towards - wheats for making noodles, and wheats for making breads. Other grains were used for things like porridges and gruels, and in some cases desireable characteristics from these grains, like disease resistance or climate adaptability, were, over time, bred into the modern varieties.
Khorasan wheat is believed to be one of the earliest strains of wheat used for making bread, though it appears to have only been unearthed again in fairly recent times. It has good qualities for breadmaking - its proteins are quite extensible, meaning they stretch. They are also strong proteins, so they handle long fermentation well. I find this latter property desireable when making sourdough bread. In recent years, as my breadmaking practices have headed towards many days' worth of fermentation time, to build flavour and better digestibility into the breads I make, grains like spelt have been passed over, as they just don't seem to handle extra long fermentation. Khorasan, on the other hand, survives very well indeed. And it tastes delicious - quite sweet, like rye.
Khorasan also has advantages over spelt at the farm end as well. Because it is quite a large grain, it threshes easily, meaning there is little wastage at harvest time. It can, as I understand it, be threshed with modern equipment, alleviating the need at the farm end to retool, adding expense for the farmer. Spelt, on the other hand, is smaller, and unless threshing equipment is modified, is quite a wasteful grain when it comes to removing husks. In the long run, khorasan may be economically viable for farmers, and thus will prove to be cheaper for us bakers to buy.
If you can get your hands on Khorasan flour, I recommend it highly for breadmaking. You can use it straight, or blend it with regular flour with great results.