Common Lisp the Language, 2nd Edition
The generic function make-instance creates and returns a new instance of a class. The Object System provides several mechanisms for specifying how a new instance is to be initialized. For example, it is possible to specify the initial values for slots in newly created instances either by giving arguments to make-instance or by providing default initial values.
Further initialization activities
can be performed by methods written for generic functions that are
part of the initialization protocol. The complete initialization
protocol is described in section 28.1.9.