Guitar Gurus, recomend a good book or video on scales
 

As a youngin I played trumpet and learned all my basic music on the horn (time signatures, keys, sharps/flats, blah, blah, blah)
The I started noodling on guitar and there is all this talk of 'scales' and after many moons I still don't get scales.
I learned the pentatonic scale (I always called it the blues scale because... well... that is what I use when I play the blues) and I can do the basic chromatic scale but feel I'm missing something here.
Any suggestions?
TIA