i used to work for one of the uk's larger training companies (the instruction set) and we were approached by Addison-Wesley UK to turn one of our c++ courses into a book. i had written about half of the course, so i said sure - how hard can it be?

the answer was: very hard.

when you are presenting a training course, you can do a lot with personality, hand-waving and stuff you had just read about the previous day. this does not work for a book. i found even transposing the course to book chapters really hard, and i eventually said "no can do".

i did do some tech review stuff for them afterwards, and got a couple of hardbound volumes of knuth as payment.

bottom line - writing a book is hard!