The collection of chapters in this book present the concept of matched filters‎:‎ response characteristics ‎"‎matching‎"‎ the characteristics of crucially important sensory inputs‎,‎ which allows detection of vital sensory stimuli while sensory inputs not necessary for the survival of the animal tend to be filtered out‎,‎ or sacrificed‎.‎ The individual contributions discuss that the evolution of sensing systems resulted from the necessity to achieve the most efficient sensing of vital information at the lowest possible energetic cost‎.‎ Matched filters are found in all senses including vision‎,‎ hearing‎,‎ olfaction‎,‎ mechanoreception‎,‎ electroreception and infrared sensing and different cases will be referred to in detail‎.‎