I have tried to find this selection through the Phoenix Public Library and could not locate it, so I asked the library staff for assistance. Please find below a "copy and paste" of the response:
I am sorry that Phoenix Public Library does not own the 1991 title The Poison Pen. In fact, only two libraries in the valley still show as owning it, Glendale Public Library and Maricopa County Library District, according to WorldCat, a global catalog of library catalogs.
If it is a future title for you book club, you could try getting it through our Interlibrary Loan service. The link to this service can be found on the homepage of the library at http://www.phoenixpub... at the far right margin at the bottom. It could take several weeks for us to get, if we can secure a loan from another library.
Another possibility would be to attempt to get it directly from one of the libraries in the valley that owns it. You could call the libraries and ask about the availability and what it would take to check it out. Here are their phone numbers:
Glendale Public Library 623-930-3537
Maricopa County Library District 602-652-3000
Hope this helps.