gear isnt mentioned in this book. only any kind of gear that emits or alters light e.g. filters, gobos, wireless triggers etc. light is what makes photos - not fancy cameras / lenses. so from this perspective alone this book is a snip.
the author has seemingly won a heap of awards for photography - check his website.
light is explained in all its facets including, colour temperature, colour balance, light quality and quantity etc etc.
the book is divided into 5 chapters - understanding light, ambient light,flash photography, studio flash, manipulating the image. i think this book has helped my photography as i can now understand what i need to do to the light to get the image im after.
most of the book deals with people photography, and flash in particular - so this may put you off. i dont have a flash yet but its on the wish list.
all in all id recommend to anyone. ive read it from cover to cover - excellent.