I am writing a book about the End-Time. I believe that a global stock
market crash will cause the world to abandon the use of currency and
go to a checkless, cashless system. I need a professional view of the
chain of events that could take the world from a global crash to a
moneyless system. I also need to need to know what the steps would be,
in laymen's terms, of course.

A global stock market crash would encourage the use of cash, not lead
directly to abandoning cash. Some people make a decent living
speculating on exchange rates a few minutes from now or tomarrow.
Extensive inflation of the everybodies currency or extensive
counterfiting would make cash unattractive. Governments might decide
to illiminate cash to slow ilegal contracts, tax avoidance and other
kinds of crime. Government wanting details on everybodies activities
might result in making everything resembling cash ilegal.
 Cash is convenient for small transactions. Cash allows transactions
with false identities. Cash helps keep big brother out of your face.
Bartering and other substitutes for cash will appear, even if
government ruthlessly try to surpress them.  Neil