Classify a book as "Required" if the book is, in your design of the syllabus, necessary for student success in the course. At least half of a book classified as "Required" should be accounted for in the syllabus as assigned readings and problem sets. When asking students to purchase a book, the focus should be on what they need in the course, rather than what they need to reference over their time at Bowdoin or keep in a home library.
Classify a book as "Optional" if it will be lightly used and/or is not essential to a student's success in the course. The library purchases a physical copy of both required and optional books (with some exceptions due to the power of publishers). Consider whether your class enrollment's need for the book can be covered by the physical copy on reserve at the library.
Consider not adopting a book as Optional at all if the students will be asked to read less than 20%. A range of pages or a chapter will be most accessible as a scan uploaded to your Canvas course. Or, the library can purchase a copy for reserve.
