This paper will review some of the recent developments in the area of high-brightness electron beams. Most of the paper will be devoted to emittance compensation concepts relating to high-brightness beam production in photoinjectors. Recent interpretation of emittance compensation and the residual emittance after compensation in terms of wave breaking has provided valuable insights into the process. Wave breaking also appears to have an influence on ernittance growth and halo production in transport lines, which we will briefly discuss. There has been advances in understanding the ernittance growth of bunches in circular motion, particularly related to the cancellation of longitudinal and transverse energy-independent forces. Finally, some non-intercepting bunch length and emittance diagnostic approaches will be reviewed.