A trend I’ve noticed, not only in a book I reviewed recently but in other situations, is the profligate use of trademark symbols (® and ™). Unless you’re the trademark holder yourself, there is no real need to use them: just capitalize trade or brand names if you’re referring to them specifically, or use the generic equivalent if you’re not.
Here is what the Chicago Manual of Style has to say about this:
Brand names that are registered trademarks — often so indicated in dictionaries — should be capitalized if they must be used. A better choice is to substitute a generic term when available. Although the symbols ® and ™ often accompany trademark names on product packaging and in promotional material, there is no legal requirement to use these symbols, and they should be omitted wherever possible. Note also that some companies want people to use both the proper and the generic terms in reference to their products (“Kleenex facial tissue,” not just “Kleenex”), but here again there is no legal requirement. (Chicago Manual of Style, 15th edition, 8.162, p. 365)
I think that writers feel they must put the symbols in because the trademark holders do so, especially if, as was the case with one of the authors of Arthritis Without Pain, they have an ongoing relationship with the company holding the trademark. But the trademark holders insert them because they have to, to assert their trademark rights; you don’t, because it’s not your trademark.