The biochemical and mechanical basis of insect flight has captivated the interest of biologists for decades. This chapter presents a brief review of the approaches used and results obtained by investigators intent on understanding the chemomechanical basis of contraction in insect muscle. We are much closer now than we have ever been to understanding the details of the contractile mechanism. This has been in large measure due to the great expansion of tools available to us, and the increasing number of investigators interested in the problem. We start with an overview of the physical methods used to investigate the mechanical properties of insect flight muscle (the biochemical and single molecule methods are covered in the chapter by Sparrow/Geeves, this volume). The physical methods are largely based on analyzing the response in muscle force to perturbations in muscle length. Next, we present a contemporary view of the contractile mechanism, based on these methods. We discuss the role of myosin in relation to its interaction with actin and other proteins of the myofilament lattice, focusing on those factors that determine muscle kinetics. One of the distinguishing characteristics of insect musculature is the extremely wide range of contractile speeds displayed by a diverse set of muscle fiber types. The chemomechanics of Lethocerus and Drosophila flight muscle are discussed and compared, highlighting recent experiments designed to elucidate the role of specific structural regions of the Drosophila myosin heavy chain in setting muscle fiber kinetics. We conclude the chapter with a brief discussion of the highly specialized structural proteins ancillary to myosin and actin that enable the high power output required for flight.