The book covers basic and advanced modules in axiomatic decision theory, intended for graduate students and working researchers. It includes cover all the proofs of all axiomatic results being presented. The book is intended to succeed classic references such as Fishburn (1970) and Kreps (1988), which are acclaimed for their mathematical completeness but getting older and need to be supplemented with more recent advancements. Although there are books on decision theory covering recent advancements, there is a need for a book that covers all the proofs in axiomatic analysis so that graduate school students can fully catch up with the field.