Books on Modular Railroading

If you are in n-scale, n-trac publishes a nice book designed to lay flat on a table for modeling purposes that goes into everything you need to know about building a n scale module. It doesn't translate to larger scales because the larger scales take so much more room to do anything. I don't know if n-trac has a web page.
 
Thanks Catt, I tried doing a "Google search" before posting, but I got everything but "Ntrak." The NTRAK MODULE HOWTO BOOK listed for $10.00 is the book I got. I would highly reccommend it to anyone in nscale. At $10.00 a copy it is probably one of the best book bargains in model railroading.