Is there available a reference book that comprehensively covers all german armor for the 39-45 period.

Or is it a case of just buying books on a specific vehicle?

I have Warplanes of the Third Reich by William Green which does the same for aircraft. Around 680 pages but perfect reference for every version and variant made.

I can't think from the top of my head of a book that covers it all and that covers it good. Each panzer type had so many different subtypes and that is not even talking about the conversions that a lot of the vehicles had as well.

I think you'd be better off with vehicle specific books. Yes it is a bit more expensive but then again the info is better and more complete. You might look into the Nuts n Bolts series and the Panzer tracts series. They really go in depth on vehicles. from first productions through all the modifications and conversions. They are pretty good value for the money.

Many thanks. I will check them out.