Here you are seeing the Lisa's CPU board..The most obvious component here is the large ceramic packaged Motorola 68000 processor. Underneath it there are two ROM chips providing the Lisa's start up boot ROM. Other components of this board are the unique MMU, video state ROM, etc... The picture was taken of the board on top of a large anti- static bag sitting on my dining room table. (Yes, I've a cheap plastic purple table cover - I'd say table cloth, but it's plastic.)
The CPU board plugs into the motherboard in the 2nd slot from the back of the machine and has a blue clip on ear on one side, a brow on the other. The motherboard has color coded lines to help you plug the CPU board into the right place. If you should switch the CPU and I/O boards accidentally, no problem, as they're not going to fit in each others' slot.