Here's why:
* Published vs. Unpublished: Stevens was a prolific writer, but not all his poems were published during his lifetime. There are many poems found in his notebooks, drafts, and personal papers that haven't been included in collected editions.
* Definitive Collection: Even within published works, there is debate about which poems constitute a "complete" or "definitive" collection. Some editors may include fragments or early drafts that others deem incomplete.
* Continuous Creation: Stevens revised and re-worked his poems throughout his life, so there are multiple versions of some poems. Which version counts as "one poem"?
Instead of an exact number, here's what we know:
* Stevens published several collections of poems during his lifetime, including "Harmonium," "The Man With the Blue Guitar," and "Opus Posthumous."
* "The Collected Poems of Wallace Stevens" (edited by Frank Kermode and Joan Richardson) is considered the most comprehensive collection, but even that doesn't capture all of his writing.
If you're interested in exploring Stevens' poetry, I recommend starting with these collections and then diving into the more specialized scholarship surrounding his work.