If the person is a rank beginner at doing their own car repairs the Factory Manuals are the most expensive way to go - but at least they have it all complete and correct, even if the terminology used goes over their head a bit.
The Chilton and Haynes manuals are the most dangerous books out there to use as the primary reference when placed in the hands of a totally clueless noob - because those books have some stuff slightly wrong and others totally wrong, and the newbie doesn't know enough about cars to tell what's right and what isn't.
The book writer (on behalf of the publisher) took one or two cars apart and photographed the process, and they ASSUME that they're all about the same - which is a very dangerous assumption to make.
They'll get the whole transmission torn apart, wondering why the pictures don't look right - and THEN figure out the book is way wrong because the instructions are for a different transmission model...
-->--