"The evolution of practice research can be viewed as a 21st century development. As it will be defined and illustrated in this volume, it has been influenced by multiple forces. One of these forces is represented by the wave of interest in evidence-based practice that prioritizes the use of rigorous scientific methods in the form of random control trials (RCT) in order to determine service effectiveness. In particular, the central role played by the concept of "fidelity" to the procedures required to guarantee outcomes similar to those demonstrated in multiple RCT studies has generated concerns among researchers and human service practitioners attempting to take into account the diverse needs of service users and the diverse capacities of service providers. These developments have generated renewed interest in qualitative methods and what Flyvbjerg (2001) calls "the science of the concrete" that is defined in the first chapter. We view practice research as a form of evidence-informed practice that involves a wide array of research designs and methods, in contrast to the narrower emphasis on experimental designs that characterizes evidence-based practice"--