I can recommend Sly Arena's "the Speedliter's Handbook"
Yes it is a book about Canon Speedlites Yes, it is easy to substitute Nikon Speedlights where the book uses Canon Speedlites Yes, most of the book discusses flash photography in general and is not flash unit specific Yes, it is one of the most easily understood books on flash photography Yes, you will learn pretty much anything you need to learn about on and off camera flash techniques No, we won't think less of you if you read a book written about a Canon product.
Gear: Camera obscura with an optical device which transmits and refracts light.
Comments
Yes it is a book about Canon Speedlites
Yes, it is easy to substitute Nikon Speedlights where the book uses Canon Speedlites
Yes, most of the book discusses flash photography in general and is not flash unit specific
Yes, it is one of the most easily understood books on flash photography
Yes, you will learn pretty much anything you need to learn about on and off camera flash techniques
No, we won't think less of you if you read a book written about a Canon product.