Nucleosynthesis in stars is the main evolutionary process affecting the chemical make-up and energy balance of the Universe. Most star formation in the local Universe takes place in the ``normal'' disk galaxies, those whose sizes and luminosities are not extreme (cf. the luminosity function in Kim & Sanders (1999) for instance), but whose other properties span wide ranges on many axes such as density, intensity, metallicity, extinction, or light-to-mass ratios. This great diversity in properties, and the complex mix of physical conditions within each system, have frustrated attempts at deriving simple models for the behavior of these ``unremarkable'' galaxies. Surveys of galaxies in the local Universe have thus become particularly valuable for codifying the empirical evidence. Infrared surveys are well suited to pursuing questions related to star formation, since current and recent star formation is preferentially expressed in the infrared.
This review will highlight recent advances derived from infrared surveys using primarily the Infrared Space Observatory (ISO; Kessler et al. 1996) in understanding normal galaxies, defined as those powered by nucleosynthesis with negligible contributions by an active galactic nucleus. Because of the diversity in properties and of the ease of detecting normal galaxies out to several hundred Mpc, survey design and sample selection determine what questions can be addressed with a given survey. Conversely, statistical results can only be interpreted in the context of the sample they are based on.