focused on expressiveness through simplicity
programming for operating systems
speed execution
no virtual machine
software engineering

minimal syntax
all values are objects
prototype-based object model
everything is a message

all messages are dynamic
code is a runtime modifiable tree
delayed evaluation block
differential inheritance
dynamic and multiple inheritance

strong type
design by contract
genericity

small
embeddable
open source

self
smallTalk
Eiffel
C (for hardware support)