Visualizing mammalian development presents an obvious problem: embryos must develop in utero. That makes them a lot more difficult to see under a microscope than a zebrafish or a frog that develops as a free-standing egg. Extensive work has been done to develop embryonic culture techniques for external development of mouse embryos, allowing imaging approaches to be applied. Early efforts by members of Scott Fraser’s lab (including myself) provided a protocol for growing d 6.5-9.5 mouse embryos on the microscope stage. The December issue of Cold Spring Harbor Protocols features Imaging Cell Movements in Egg-Cylinder Stage Mouse Embryos from Oxford University’s Shankar Srinivas. The article describes a method for isolating and culturing much earlier mouse embryos, as well as an approach for time-lapse imaging as those embryos develop. While cell movements can be followed using light microscopy alone, the increasing variety of transgenic fluorescent reporter mice makes studies of cell movement easier and more informative. As one of December’s featured articles, the protocol is freely available to subscribers and non-subscribers alike.