Mackam...
What do you mean by 'dispatcher'? The term is used a bit differently in the UK than elsewhere and could refer to 2 jobs that are distinctly different. The term in the UK is the guy who is out walking the ramp in all weather doing load sheet, pushback and everything else concerned with turning an aircraft around.
In most parts of the world however 'dispatcher', more commonly known as 'fligh dispatcher' is the one who plans the flight from start to finish. This includes weather briefing, route analyses, fuel planning, liaising with air traffic control, aircraft performance calculations and that is just a small part of it. It is an interesting job and there is no limit to how deep you can go with regard to learning the various aspects.
There are no real books as such for ramp dispatch as it mostly in house training and OJT.
Flight dispatch, there are not many definitive texts exclusively for it either but there are certain books that are used for pilot training that double up as excellent references but you would need to know where to pull out as some of these texts go beyond what you might need to know.
Am happy to provide some titles if you wish, just let me know.
All the best,
D.O.G