Oral drug delivery has been an important part of drug delivery and was often linked with tablets, capsules, syrups etc during the discussion about delivery through gastrointestinal tract. Advancements in pharmaceutical sciences and enormous research in the field of drug delivery has laid newer concepts leading to the advent of advanced dosage forms with modified release leading to enhanced therapeutic efficacy. Similarly oral drug delivery has witnessed a change. The book as it is in present form is compilation of theories postulated with regards to oral drug delivery and data related to research work. Different facets of oral drug delivery from conventional to novel have been described through self explicit figures and relevant examples. Underlying basic concepts of different processes have been explained for better understanding of the subject. This book will serve as ready reference for undergraduate and postgraduate students and will cater to the scientific need of those interested in research in oral drug delivery.