This paper is part speculative, part technical, and mostly discursive!
The paper is also comprehensive and should be readable by a large
fraction of the software community.

The conjectures of the paper are based on more than 30 years of
extensive experience in computing and software systems development: in
the formal, abstract specification of software system architectures,
and in their stepwise implementation. The conjecture of the paper is
this: For a software house, a producer of products, to be able, in
future, to compete effectively it must possess: (i) deep and broad
(large scale) problem domain knowledge represented in the form of
`mathematical theories of application domains', (ii) ready access to
`software devices and mechanisms', and (iii) otherwise pursue
development steadily using a large variety of `design calculi'.

The paper will define the single-quoted concepts, and will illustrate
large-scale applications.