Houghton Mifflin Harcourt Kids Discover ©2018 is a social studies program that delivers engaging content in the form of highly visual and student-friendly Magazines with accompanying Teacher’s Guides. Rainbow developed content for both California and National Editions of the Teacher’s Guides for Grades K–3, a total of 12 Teacher’s Guides. Additional components created by Rainbow included more than 1,400 ancillary pages (approximately 630 for the California edition and 830 for the National edition) and 18 Online Literature Selections for Grades K–6.