Into the Void (Spelljammer: The Cloakmaster Cycle, #2)

Plunged into a sea of alien faces, Teldin Moore isn't sure whom to trust. His gnomish sidewheeler is attacked by space pirates, and Teldin is saved by a hideous mind flayer who offers to help the human use his magical cloak—but for whose gain? Teldin learns the basics of spelljamming, and he seeks an ancient arcane, one who might tell him more.