The first documentation for the original 1984 Macintosh was available only in the form of photocopied sheets that could be obtained from Apple, it was not until 1985 that they were published in the form of a book that was available to the general public. The first version had three volumes, which covered the original Mac 128, and the 512 ("Big Mac") and Mac XL (Lisa) models. When the Macintosh Plus was released, a fourth volume was added, detailing the changes to the system software introduced with that model. A further "delta" manual, volume 5, was introduced with the Mac II line in 1986. This manual discusses colour QuickDraw, as well as the Mac II and Mac SE hardware and other new software components.
By the time of System 7, released in 1990, the Inside Macintosh "delta" model was becoming seriously stretched. Nevertheless the details of System 7 were documented in the immense Volume 6.
Shortly after this, Apple revamped the entire Inside Macintosh series, breaking it into volumes according to the functional area discused, rather than specific machine models or capabilities. In this form, the series was far more coherent and a much better reference for programmers. As new functionality was added to the Mac OS, a new volume could be written without invalidating those which had been published earlier, in contrast to the first series, which became increasingly out of date over time.
Inside Macintosh was published by Addison Wesley.
In the late 1990s, Apple ceased to publish Inside Macintosh as a printed book, instead making it available as a CD-ROM, and online. Since then, the CD variant has been phased out, though Apple developers can still receive online documentation as part of the developer CDs. In its online form, the information is much easier to maintain. Some developers still prefer a printed format however.