Whether McGrath's book will be useful to you or not depends on what kind of architectural photography you want to do. I bought a copy; his book is mostly about taking color photos of newer buildings using lots of artificial light if necessary. I sold the book because I am interested in taking pictures of historic buildings in B&W using available light.
I do not know who McGrath's clients are, but would gues that they include architests and colored-glossy magazines.
Good luck.
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