Thoroughly updated, streamlined, and enhanced with pedagogical features, the twelfth edition of Barresi and Gilbert's engages students and empowers instructors to effectively teach both the stable principles and the newest front-page research of this vast, complex, and multi-disciplinary field. This much loved, well-illustrated, and remarkably well written textbook invigorates the classical insights of embryology with cutting edge material, and makes the most complex topics understandable to a new generation of students. Designed with the undergraduate student in mind, this new, streamlined edition now contains studies of plant development, expanded coverage of regeneration, over a hundred new and revised illustrations, and deeply integrated active learning resources that build on the text's enthusiasm and accuracy. This is a text designed to make students become excited about how animals and plants develop their complex bodies from simple origins.