The booklets do not explain the meaning of "HUB". The dictionary says hub being the centre of activity – as the booklet covers many manufactures this may be the  reason behind the word hub.

Each booklet covers the following :-

Marklin-trains, accessories, cars, track. Faller-various kits.  Wrenn - Track. Tri-ang.

X-acto knives & tools. Master Models. Kirdon Kits & point motors. Hornby Dublo. Trix. Peco.

Jamieson Kits. Romford. Hamblings Fittings. Nucro Products GEM. Britains. Rivarossi.

Exley Coaches. Ratio. C.C.W. Coach & Wagon kits. Paints by Celspray, Ratio & Reeves.

Bilteezi sheets. Anorma Building Kits. Modelcraft Plans & Kits. E.R.G Card Parts.

Crescent Signals. Hammant & Morgan

Total pages 160.