The earliest known printed citation of 'between a rock and a hard place' is in the American Dialect Society's publication Dialect Notes V, 1921:
"To be between a rock and a hard place, ...to be bankrupt. Common in Arizona in recent panics; sporadic in California."
Between a rock and a hard place. The 'recent panics' referred to in that citation are undoubtedly the events surrounding the so-called US Bankers' Panic of 1907. This financial crisis was especially damaging to the mining and railroad industries of the western states.
In 1917, the lack of funding precipitated by the earlier banking crisis led to a dispute between copper mining companies and mineworkers in Bisbee, Arizona. The workers, some of whom had organized in labour unions, approached the company management with a list of demands for better pay and conditions. These were refused and subsequently many workers at the Bisbee mines were forcibly deported to New Mexico.
It's tempting to surmise, given that the mineworkers were faced with a choice between harsh and underpaid work at the rock-face on the one hand and unemployment and poverty on the other, that this is the source of the phrase. The phrase began to be used frequently in US newspapers in the late 1930s, often with the alternative wording 'between a rock and a hard spot'.
Interesting Matt !! The first time I heard the expression when I think his name was Brian Keenan, one of the Beirut hostages used it & i think he used it for his book title !
@happypat I think the memoir of his time as a hostage in Beirut was called, "An evil cradling" but he must've used this expression at some point. I remember hearing him read his book on radio 4 which was a very raw and emotional experience.