Might I suggest that the distinction may have more to do with the practical manner in which grunt can be measured ?
The turboprop unit, in the same way as for piston power units, is most conveniently graded according to brake shaft horsepower (or whatever units you might prefer) where the grunt can be dispersed via the means of some external load hooked onto the shaft (hence "brake"). The propeller then converts most of the power coming up the shaft into thrust, which is what the pilot wants. Thrust ties the engine and the propeller controls together and is not simply a matter of what the engine is doing. Hence propeller power units are most conveniently rated in terms of the available power - kW, HP, whatever ...
For the jet/fan, where the useful output is via the exhaust, it is more convenient to measure the thrust, hence kN, lbf, whatever...
The other concern is that the analysis of the aircraft/engine combination is rather easier with a jet/fan unit.
For the benefit of those of us who read books occasionally, what was the book ?
[This message has been edited by john_tullamarine (edited 04 July 2001).]