You won't find any books that go into field coding in much detail. I did contribute to one some years ago (
Word Hacks, by A Savikas, published by O'Reilly Media in 2005 (
Word Hacks - O'Reilly Media)) but even that doesn't cover anywhere near as much as the tutorials I've written on the subject. Indeed, my tutorials probably contain more detail than you'd find in all the books you could buy on the subject.
To start with, check out my
Mailmerge Tips & Tricks:
https://www.msofficeforums.com/mail-...ps-tricks.html
To see how to do a wide range of calculations in Word, check out my
Microsoft Word Field Maths Tutorial:
https://www.msofficeforums.com/word/...-tutorial.html
To see how to just about else you might want to do with dates in Word, check out my
Microsoft Word Date Calculation Tutorial, at:
https://www.msofficeforums.com/word/...-tutorial.html