ballistics, etc.

[Peter Trachtenberg]

It seems to me that TRP's historical and scientific perfectionism--his 
aforementioned meticulousness when it comes to adhering to the factual 
(or should I say making the factual adhere to his fiction?) has an 
antecedent in Joyce. When writing ULYSSES, JJ mercilessly badgered 
friends and relatives for reminiscences and news clippings of June 18. 
You can read about it in Ellman's biography. As an imaginative writer, I 
also find it necessary to find a factual anchor for speculation, partly 
for my own sake, lest I succumb to the creative equivalent of altitude 
sickness, and partly for the sake of the reader. Because when you set out 
to invent a new world, you have to give the reader something that 
resembles the comforting earth on which he--or she--used to stand.