Ruth
The club I'm a member of has had such a rush of new members that we've had to set up a Train the Trainers course. This thread will roll for several days by which time I hope the club webmaster will have posted up the guidelines we are using, and I will post the link for that. One of the things that was discussed there was books and the feeling was the Rowley's book is now going out of date in that it was written before the scroll chuck was universally available and used. He only mentions it's use in passing, not referring at all to it in use.
His tool guidance is good, but a strong recommendation goes to a more up-to-date book, Mike Darlow's "Fundamentals of Woodturning".
I would add to that Richard Raffan's book "Turning Projects". And there is also the Woodturning monthly magazine
Please be aware that one cannot really learn wood turning in isolation and that your step-mum needs to look for an active local club or be prepared to go on a course. What she learns from either of these will be backed up by a book.
There is also the other little factors that need to be known right at the beginning and that like many hobbies, the start up costs are quite high in terms of tools and ancillary equipment. Unless you have access to a club, or another turner, who has equipment she will require a grinder for tool sharpening, and then she'll fancy a bandsaw for the initial shaping of wood, and a bench drill is useful ..... and so on. I discovered some time back that to take up a new hobby with reasonable commitment involves a layout of around £1000 - don't be put off by that as it can be spread over quite a time period, unlike say sub-aqua where you need to spend that to begin with.
As others have said, well done in coming here as I think this is the prime wood turning forum in the UK, and is full of like-minded people who are very supportive on new turners.
Rob