Most modern history books leave it out all together (gee, I wonder why) and speak not a word of it, nor much anything the north did from Crittenden to Fort Sumter, other than inaugurating Lincoln plus some skewed version of the south firing on the Star of the West.
To find any mention of Corwin in a history textbook, even a one-sentence reference, you pretty much have to go back over half a century. Even the small number of recent scholarly works specifically dealing with the history of the amendments to the constitution give it, at most, a page or two. Having researched the Corwin amendment, I had to go all the way back to an account published in 1933 to find any substantial material about its coming into being, and that was in an 8 page chapter from a book dealing specifically with the time period in between the first and last southern states to seceed. Prior to that, mention of Corwin seems to have been payed at least a small ammount of attention. But today, there is barely anything at all on it. Not even in those rare books by extremely bored authors that attempt to give a biography of President Buchanan!
I've always found this interesting considering that most of the other constitutional amendments that passed yet never recieved the ratification needed are payed at least some attention in the history books. The "Equal Rights Amendment" is a favorite topic of all history textbooks, often due to their liberal slant. Additionally, they often throw in the child labor amendment into the chapter on progressivism. Some even mention the titles of nobility amendment, albeit briefly, but still there are chapters books (and conspiracy theory pamphlets) about it if one takes a few minutes to look around and find them. But nothing at all on the Corwin amendment. I even know of cases where bigwig Yale and Harvard constitutional law professors have admitted being first skeptical then shocked after discovering that it exists. Mysteriously, or perhaps not so mysteriously, it has been scrubbed from the pages of our history books. IMHO, the reason is all to clear - the Corwin amendment gives concrete meaning to what is otherwise an obscure and seemingly senseless statement in Lincoln's first inaugural, and that meaning isn't a very pretty one.