I think lynda.com flex materials are wayy too shallow just
barely scratching a surface,
I personally recommend following :
http://www.theriabook.com/ plus it comes with a free dvd,
at first I was little skeptical about that book, but IMHO,
this is the most advanced book I have ever found, and I have
safari subscription so I have looked at several of flex books so
training from the source is also a good book.