What is Judy?

[Robert Moskowitz]

I am trying to build Miredo 1.1.5
(http://www.remlab.net/miredo/devel.shtml.en)

I have followed the rpmbuild instructions from:
http://www.owlriver.com/tips/non-root/ (after all, I am principally a 
Centos person, and know where to find out htings about Centos and 
figured this will not be different in F10), and have the miredo source 
in ~/build/miredo-1.1.5.

I run ./configure (as the INSTALL text file tells me to do) and get the
error:

checking for Judy.h usablity... no
checking for Judy.h presence... no
checking for Judy.h... no
configure: WARING: If you don't care about scalability, re-run configure
with ' --without-Judy'.
configure: error: Required Judy dynamic arrays library missing.