Freeman’s briefest, least expensive introductory astronomy text.
Discovering the Essential Universe, Fourth Edition (DEU 4e) is designed to help students overcome common misconceptions about astronomy. It provides up-to-date explanations of core concepts in a flexible and student-friendly text, supported by an impressive collection of multimedia resources developed by astronomy education researchers.
This is a textbook I read for intro to astronomy. For a textbook I felt it was well written and engaging enough to read through the whole thing, even the chapters not assigned.