I've heard assertion that Piers Anthony is misogyny for quite a while now, but on examination, I just don't see that assertion proven out in his Xanth books. I'll go over my my reasons. You are, of course, free to disagree.
If Piers was a misogynistic writer, I would expect that the women in his books would get their comeuppance violently, or at least firmly. In his books, the heroes don't take the women in hand very well and do not use violence or compulsion. If Anthony is a misogynist, he's got to be quite the wishy-washyist misogynists on the planet.
Another test for misogyny is the no-win situation for women: if women have sex, they are sluts, but if they don't, they are prudes. Again, I don't see that in Anthony's books. His men aren't constantly putting women into no-win situations. I don't see slut shaming. His characters don't utter verbal violence. I don't detect any sort of trollish behavior at all (other than as character traits for certain characters). That's another strike against misogyny.
I'm not satisfied yet, so I'll ask another question: if I was a misogynist, would I get any satisfaction from reading these Xanth books? Honestly, I don't think so. There is one character who is a woman hater in one story, but he's just one character among many, with a remainder who don't utter hatred of women, and the woman-hating character doesn't even hog the screen time. In the end, the woman-hater gets married, which is a very strange fate for a man in a misogynistic book. I don't see that fate appealing to a woman hater. So, a basic failure to appeal to the misogynistic audience strongly indicates that the books are not misogynistic.
As I've just reread Anthony's early Xanth books, I find that the women there are depicted to in a highly objectified style reminiscent of pinup girls from the 40's or 50's. Piers's humor reminds me of the type of gender humor that you hear in mid-century radio comedies and films. When I checked up on Piers Anthony's age, the result confirmed my observation. He was born in the thirties to become a teenage in the late 40's through the 50's. In other words, his depiction of women in the Xanth books is consistent with the cultural female narrative that dominated the United States in the mid-20th century.
There's a word for the male attitude towards women in the mid-20th century. That word is "sexist." It is this very narrative of sexism that led to feminism and bra-burning. The male culture asserted a narrative of women which asserted that women were shallow, assigned women the traits of illogic and nonsense, that a man was doomed to love a woman, and that once he caught her he'd have to put up with all her feminine silliness. The ultimate sexual purpose of a woman was to be available to her man. It's that narrative that I see in the early Xanth books.
In A Spell For Chameleon, young Bink goes around the countryside bumping into women, having all sorts of nearly-erotic adventures, meeting all sorts of women making (or not making) all sorts of enticing offers. The work itself is a flat-out sexual tour-de-force making fun of the sexual revolution. Bink doesn't have magic (he's a virgin), wants to find his magic (lose his virginity), and so goes on a long quest which ends with him getting laid. Of the many offers for sex he does get, they all come with catches, so buyer beware. In all instances, the women were't what they seemed, so keeping it his pants on proved pretty smart. In The Source of Magic, the story begins with three henpecked husbands who had discovered that their perfect girls weren't so perfect, and so happily went off on an adventure to get away from their shrews. This once common comedic trope died upon meeting feminism and the easy availability of divorce. That very comedic trope only works in the context of sexism.
In Anthony's later works, where he discovered that he had a much younger audience for his books, he toned down the sexuality and played up the teenage anxiety. The man wasn't dumb and his books sold, sold, sold to both boys and girls.That's a weird thing if your misogyny causes girls to flock to you books.
Are any of Piers Anthony's other books misogynistic? I can't fully answer that question because I haven't read everything that he's written. You can safely assume that anything from the 70's was sexist simply because his target audience was young professional men, but can you assume misogyny? On further investigation, I would certainly expect to find misogynistic tropes, because these were fairly common in the era, but you need more than a trope to make a misogynistic work. Misogyny is not incidental, occurring here and there, but structural, laid deeply into the structure of the work.
So my opinion is that Piers Anthony write sexist books but not misogynistic books. I can't definitively proclaim that his sexism transformed or softened over the years, but it is my opinion that he did grow more inclusive as the years went by, lessening the sexism as he learned that he had a wider audience.
Way back in the 80's, I remembered a great number of women who loved the Xanth series. If it was so sexist and mysogynistic, why did those women like it?
In the land of Xanth, everybody had magic, even women. Anyone could be born with magician level magic, even women. Women had job. Women were heroes, villains, companions, hazards, and monsters. In Xanth, women could literally be anything.
Piers Anthony may have been sexist, but Xanth itself was feminist. At a time when women in fantasy were a strange sight, the Xanth novels brimmed with women in every sort of role. Because Piers began with the most sexist stereotypes, but strove to never repeat characters, as he wrote more novels, the variety of his female characters increased. Xanth became more inclusive over time.
So, as you consider whether something is sexist, keep in mind that sexism is not a binary. Some parts of a work can be sexist while others parts can be egalitarian or feminist.