I don't think there are invalid subjects for poetry. I've read or written poems on everything from garage sales to butter to gruesome deaths to euphoric sex. If you want your poetry published there may be subjects different publishers may object to, but that's up to the publisher's taste.

It's anything that *pops* into your head.

The only one I can think of is sex crimes against kids. Some people write poetry about the most horrible things that happened to them and often find it healing. But I don't think they intend them for publishing. This one is very long and very sad. This is how it ends.... It's called For Children Who Were Broken - The journey is not so lonely as in the past its been. More of us are strong enough to let the growth begin. But while we're trekking up the mountain we need everything we've got, to face the adults we have become, and all that we are not. So when you see us weary from the day's internal climb ... When we find fault with your best efforts, or treat imperfection as purposeful crime ... When you see our quick defences, our efforts to control, our readiness to form a plan of unrealistic goals ... When we run into a conflict and fight to the bitter end, remember ... We think that winning means we won't be hurt again. When we abandon OUR thoughts and feelings, to be what we believe YOU want us to, or look at trouble we re having, and want to blame it all on you... When life calls for new beginnings, and we fear they are doomed to end, remember... Wounded trust is like a wounded knee ... It is very hard to bend. Please remember this when we are out of sorts. Tell us the truth, and be our friend. For children who were broken...it is very hard to mend. It touch my heart because I was one of those children.

I don't think a poem about another poem or poetry would be well received. I have never heard of a poem about a poem/poetry.

I dont think any subject is invalid. I consider poetry to be a recording of feelings the writer has about something at a given moment, or something that is on her mind. As for publishing: I am sure you can get someone to print anything, it depends on whether you want certain insights into your soul to be published or not.

None. We are human beings. We might write poetry - or use any other art form for that matter - as our "expression vehicle". We're always free to tackle any subjects we like in our own, private worlds. In free societies, we have the additional ability to share with others without censorship re: topics or slant/POV. If, however, we live where there are laws that specify what's "not ok" - then if we are citizens there, we must comply or pay whatever consequences apply. Others have already talked of "marketability" or "what publishers might find more or less valid". Those are impt commercial concerns but not a yes/no for the creative process itself. Could easily have a subject that's perfectly valid to write a poem about, but has little to no interest to publishers looking for matching interest demographics. So in my mind? There are no invalid subjects. All of life is fair game. As soon as we want to "share" with others, we become subject to "validity checks" of another type entirely .. ie .. legality in a country or marketability with publishers, etc. But neither of those is the same as a basic "validity" to creatively deal with ANY subject. :)

Invalid? Do you mean from a literal form and function perspective or from a personal opinion perspective? There really are not "invalid" subjects for poetry, but there are styles of poetry that some consider to be invalid as in proper and correct according to form and function. For instance; Some argue that prose is not actually poetry. Argue it to like an obnoxious extreme using accusations like people who worte prose can't write in iambic pantameter or Octosyllabic verse. But subjects? I don't believe there are any invalid subjects for poetry as long as it is from the mind or imagination of the person writing it. Everything is fair game. In my opnion anyway? There may be come college poetry class example that I am unaware of?