> I just want to know, if there is any book that covers PicoLisp from it's
> fundamental concepts to advanced level?
Probably not to that extend. As "real" books there is only PicoLisp-Works and
PicoLisp-by-Example by Thorsten Jolitz (perhaps a bit outdated by now).
The online references of PicoLisp try to cover the fundamental concepts in
http://software-lab.de/doc/ref.html, and also some of the more advanced levels.
> What are the differences between Newlisp and PicoLisp? As they both claim
> to be simple.
This question comes up relatively often. So I must say that despite I do not
have a deeper knowledge of NewLisp, from what I read I do not think that it
should be called a Lisp.
It is more a scripting language with Lisp syntax. Its internals, memory model
and behavior are different from what I expect from a Lisp: There are no
cons-cells, no bignums, no garbage collection, no sharing of (sub)lists, no
circular structures - in my opinion the things which make up the real power of
Lisp. Even multiple variables pointing to the same object are not allowed.
An advantage of NewLisp is that it runs also on Windows, while PicoLisp requires
a POSIX compatible system.