Pigot and Co.'s Royal National and Commercial Directory
The flysheet of the 1839 edition continues ...
"... comprising classified lists of all persons in trade, and of the nobility, gentry and clergy, resident in the towns and principal villages in the above counties. An account of every mode of convenance by railway, road and water; Post-Office regulations, &c."
Alec Whitfield has compiled indexes to surnames and place names for the Kent volume of the 1823 and 1839 editions which have been republished and are fairly readily available to researchers.
Sussex-Plus was one of the early RootsWeb lists. As well as Sussex, it originally covered Surrey, Kent and Hampshire too. Now those counties have their own RootsWeb lists and Sussex-Plus contentrates on Sussex itself.
This Kent News page may help get the distinction between Kentish Men and Men of Kent clear in your mind.
Hasted, Edward. The history and topographical survey of the county of Kent. Containing the antient and present state of it, civil and ecclesiastical; collected from public records, and other authorities: illustrated with maps, views, antiquities, &c.. Canterbury, Printed by W. Bristow (1797-1801) 12 vols. [Full text]