The so-called Boyer-Moore Theorem Prover (otherwise known as Nqthm) ha
s been used to perform a variety of verification tasks for two decades
. We give an overview of both this system and an interactive enhanceme
nt of it, Pc-Nqthm, from a number of perspectives. First, we introduce
the logic in which theorems are proved. Then, we briefly describe the
two mechanized theorem proving systems. Next, we present a simple but
illustrative example in some detail in order to give an impression of
how these systems may be used successfully. Finally, we give extremel
y short descriptions of a large number of applications of these system
s, in order to give an idea of the breadth of their uses. This paper i
s intended as an informal introduction to systems that have been descr
ibed in detail and similarly summarized in many other books and papers
; no new results are reported here. Our intention here is to present N
qthm to a new audience.