Author Vivien Gornitz, a NASA science collaborator and retired special research scientist at Columbia University’s Center for Climate Systems Research, takes readers through the basic physics of them: glaciers, ice sheets, ice shelves, sea ice, icebergs, permafrost and methane hydrates. Then she dives deep into the ongoing retrenchment of all of them, brought on by warming of the planet. She paints a daunting and detailed picture, ranging from the dramatic collapse of great Antarctic ice fronts into the Southern Ocean, to the insidious and poorly charted workings of under-glacier river systems and sudden blooms of sun-fed algae spreading across the surface of the Greenland ice sheet.