I find his books are useful, although there are generally relatively few Papilionidae in the areas he covers, and he tends to lump subspecies together, but does have all the necessary information inside, such as references to relevant publications on each taxon, type localities, recorded localities and distribution maps. He also has gazetteers of place names in the Central Asian volumes which can be helpful.
Vadim is an old friend of mine, and is due to visit me here next week. He will be bringing out the remaining parts of his series that I do not have. He will be away for about a month, so if you e-mail him he may be slow to reply in the next few weeks.
I agree with Adam here. Vadim does not seem to believe in too many races of things. I also disagree with the generic lumping that goes on. Seems that almost all blues are Polyommatus! However, I have all the books thus far published and for ID they are excellent as you only see material from the country in discussion. Dave