The Axxe is basically a monophonic version of the Odyssey (which was duophonic). It came with "Lessons in Electronic Music" (a 155 page textbook), "Instant Axxe" sheets that you could lay over the front panel that showed you patches, "Axxe blanks" (blank patch diagrams), an interface diagram (to hook it up with other synths), and a book of 50 patches.
The ARP Axxe (like the Odyssey) is also equipped with "Proportional Pitch Control (PPC), ARP's latest contribution to more expressive synthesizer performance. The triple-pad, pressure-sensitive controller lets you bend notes sharp and flat, and add vibrato, all without moving a single slider or switch."----[from the ARP Odyssey's promotional brochure]