M Programming: A Comprehensive Guide is a complete update to ABCs of MUMPS. While ABCs of MUMPS was an introduction for novice and intermediate M programmers, M Programming: A Comprehensive Guide has a new section containing advanced material. This new section addresses features such as transaction processing, networking, structured system variables, and interfaces to other standards. Five new chapters have been added, covering an overview of M for readers familiar with other languages; M and the Windows environment; interaction between M and the underlying system; transaction processing; interfacing M with other standards; and error handling. Sections on interactive programming and futures have been extensively updated. M Programming: A Comprehensive Guide is an invaluable resource for everyone who is learning or using M.