The Macintosh II, released in March of 1987 for $6500, began the era of very expensive, but very powerful and very expandable Macintosh computers. Apple was always against an "open" Mac, in which a user could easily play with the insides of his Mac and add different capabilities. Such projects were always terminated before they got anywhere. That was before Mike Dhuey began work on "Little Big Mac". Later helped by Brian Berkeley, the project grew, until it became the biggest project at Apple since the Mac 128k. The first Mac built around Motorola's 32-bit 68020 processor, it ran an incredible four times faster than the SE on average, thanks to its 32-bit data path. It was the first of the modular Mac cases. Like the Apple II models, the monitor and case were separate, allowing more expandability. Also like the Apple II, it had six slots. It was easily apparent how expandable this machine was in the features of the Mac II. It could hold up to 68 MB of RAM (shipped with just 1 MB), a staggering number back in '87, more than any other Apple computer at the time. It also had six NuBus slots, hidden behind an easy-open lid. This allowed even novice users to easily add graphics, acceleration, or networking capabilities to their new Macintosh. The Mac II didn't have a hard drive built-in, but could support one internal SCSI device (most likely a hard drive). It also didn't support an external monitor, for which a graphics card was needed to do. Though the Mac II was rather expensive, still didn't support 32-bit addressing, and pretty slow compaired to the lower-priced NeXT Computer, it still opened new opportunities for the Mac. It succeeded in making the expansion of a Mac as thorough as that of an Apple II, a computer which did similar things for its platform.

Code Names: Little Big Mac, Milwaukee (engineer Mike Dhuey's hometown), Ikki (means "bottoms up" in Japanese), Cabernet, Reno (in honor of the slots), Becks, Paris (homage to Jean-Louis Gassée), Uzi

Specifications:
Processor: Motorola 32-bit 68020 processor running at 16 MHz.
Memory: included 1 MB of RAM expandable to 68 MB, 256k ROM
Drives: an 800k floppy drive, with support for a 1.4MB Apple SuperDrive.
Expansion: 6 NuBus slots supporting full 32-bit address and data lines.
Ports: two ADB ports, two mini-circular 8 serial (RS-422) ports, and one DB-25 SCSI port. ADB Keyboard and mouse included.

Operating Systems:
Mac OS: came with System 4.1, supports System 2.0-7.01, 7.1, 7.11 Pro, 7.5-7.51, 7.53.7.55.

On the market for: 2 years, 9 months

Interesting Facts:
One of the reasons the Mac II wasn't killed like other projects dealing with expandable Macs was largely due to Jean Louis Gassée, now CEO of Be, Inc. When Mike Dhuey and Brian Berkeley worked on the project, they kept it very secret from Jobs. Gassée was a very big supporter of "opening" the Mac, and when he found out about the project he not only let it continue, but later recruited several other engineers to help out on the project.

Resources and Related Links:
Apple's Technical Information Library
David Pogue's and Joseph Schorr's Macworld Mac SECRETS.
Picture above from A History of Apple Computer.