Sensors & Signals is the 1st book from the Book Series of the same name published by IFSA Publishing. The book contains 8 chapters written by authors from universities and research centers from 12 countries. The coverage includes most recent developments in: Virtual instrumentation for analysis of ultrasonic signals; Humidity sensors (materials, preparation and characteristics); Fault tolerance and fault management issues in Wireless Sensor Networks; Localization of target nodes in a 3-D Wireless Sensor Network; Opto-elastography imaging technique for tumor localization and characterization; Nuclear and geophysical sensors for landmines detection; Optimal color space for human skin detection at image recognition; Design of narrowband substrate integrated waveguide bandpass filters. With its distinguished editors and international team of contributors Sensors & Signals is suitable for academic and industrial research scientists, engineers as well as PhD students."