Major unresolved issues in the formation of chondrules and CAIs

So much has been learned and published about chondrites and so many models have been floated (but neither proven nor refuted) that the subject has become extremely diffuse and amorphous. It is impossible to remain simultaneously aware of all the many constraints, from many different subdisciplines, that bear on nebular processes. This paper attempts to impose some structure on the situation and loosen the interpretational logjam by breaking the chondrite problem into a series of well-defined questions. Most are open questions; those that some might consider closed by now may deserve formal reexamination.