Book excerpt: Papers on Smarandache's Orthic Theorem, Smarandache's Concurrent Lines Theorem, character graph in Brauer graph's model, robust stability of switched linear systems with time-varying delay, majority neighborhood number of a graph, divisibility tests for Smarandache semigroups, Hopf bifurcation in a predator-prey model with distributed delays, and similar topics. Contributors: R. S. Maragatham, S. Asawasamarit, U. Leerawat, S. Balasubramanian, D. Senthilkumar, M. Khoshnevisan, D. Senthilkumar, Sherinjoy S. M., and others.