This document discusses the different types of tablespaces in InnoDB including the system tablespace (ibdata1), file-per-table tablespaces (.ibd), general tablespaces (.ibd), undo tablespaces (undo_001), and temporary tablespaces (.ibt, ibtmp1). It provides details on the structure and management of space within these tablespaces including pages, extents, segments, the file space header, extent descriptor pages, and the doublewrite buffer.