We report strong, amplitude modulated, oscillatory resonant transmission of electron through non-tunneling regime (E < V0) of the nanostructure called symmetric double barrier. We present thorough and complete analytical calculation and thorough numerical investigations. Amplitude of the oscillations shows spectacular waxing and waning as a function of energy E. We could not fathom anything like this before the numerical investigations. We have successfully accounted for the waxing and waning both qualitatively and quantitatively showing nearly perfect agreement. The book contains background on Quantum Mechanics, Microelectronics and Nanostructure Physics so that readers having no background of Microelectronics and Nanostructure Physics can assimilate the book completely. Content of the book is stunning and novel: not known to anybody or reported by anybody anywhere else, to our knowledge.