I bought my copy of "Say Uncle" last year when Kay Ryan came to San Francisco and gave a talk on her work. When I saw her speak, I had never really heard of her before, but left the talk totally impressed by both her work and her personality.
This book contains dozens of very short, but very poignant poems. She approaches topics from everyday life, but frequently through an almost scientific detachment. She totally removes herself from the poems and makes them universally appealing. She is the ultimate observer, able to comment on the topics in the poems without bringing preconceived notions about that topic, which lets the reader see each thing anew.
Ryan uses a technique she calls "recombinant rhyme", in reference to how the DNA of two different individuals or even species can be combined to create a chimera, or hybrid. She does a similar thing with words and parts of words, and while her poetry has little perfect rhyme, the same or similar sounds are found sprinkled around the poem, combined together to make new words. With all this "recombination", slant rhyme and other imperfect rhymes are very common. Her verse is fairly free, though there are still times when the reader can start to fall into a metrical pattern, only to immediately be derailed by an extra word or phrase. When I heard her talk about her work, Ryan said that she intentionally avoids overly metrical lines.
I wonder if these types of poems are perfect for the Twitter Age: short, witty poems that can be digested quickly but lead the reader to frequent "Ah ha!" moments. Interestingly, the common expression "say uncle" which is the title of this book, apparently comes from a British joke about a parrot (See World Wide Words: Say (or cry) uncle)