We apply recent in situ measurements of the mass density, mass distribution, and flux rate of dust particles that enter the solar system, i.e., the heliosphere, to study the properties and dynamics of the interstellar dust flux into the solar system. We show that depletion at the heliopause alters the flux for particles with mass, m10-15 kg). We show that early measurements that provided evidence for the focusing are in agreement with present estimates of the interstellar dust flux. There is clear observational evidence for all listed effects and detailed studies would be possible on the basis of more extensive measurements. We compare the in situ measurements of absolute density and mass distribution to the parameters determined for the interstellar medium (ISM). While the lack of small particles in the measured mass distribution may be a result of their depletion, the detection of larger grains may support models of collisional particle growth in the ISM. As well, interstellar particles that were found in meteorites yield evidence for the existence of large grains in the ISM, although they may be of completely different origin. We infer from the absolute densities that the dust reflects the conditions of the ISM on large scales rather than those of the local interstellar medium (LISM) in which the Sun is embedded. This supports theoretical results that the gas-dust friction scales in interstellar space exceed the extension of the LISM. From calculations of radiation pressure forces and comparison to the detected mass distribution we conclude that the detected interstellar dust particles are better described as composite grains rather than as particles that consist of pure materials, which further supports the model of collisional particle growth. ¿ 2000 American Geophysical Union