Shape coexistence in the light krypton isotopes was studied in a series of experiments at GANIL using various experimental techniques. A new low-lying 0(+) state, a so-called shape isomer, was found in delayed conversion-electron spectroscopy after fragmentation reactions. The systematics of such low-lying 0(+) states suggests that the ground states of the isotopes Kr-78 and Kr-76 have prolate deformation, while states with prolate and oblate shape are practically degenerate and Strongly Mixed M Kr-74, and that the oblate configuration becomes the ground state in Kr-72. This scenario was tested in experiments performing low-energy Coulomb excitation of radioactive Kr-76 and Kr-74 beams from the SPIRAL facility. Both transitional and diagonal electromagnetic matrix elements were extracted from the observed gamma-ray yields. The results find the prolate shape for the ground-state bands in Kr-76 and Kr-74 and an oblate deformation for the excited 2(2)(+) State in Kr-74, confirming the proposed scenario of shape coexistence.