Even for a woman as sensitive to wild animals as Grace 1Spruch, the arrival of a squirrel inside her Greenwich Village apartment one morning came as something of a surprise. She had always loved the squirrels she saw in Washington Square Park, but she never met one so forward as the one climbing up her rubber plant. Dr. Spruch didn't know it then, but this was the beginning of a strange and wonderful relationship.Gradually, other squirrels began to climb the fire escape to the Spruchs' fifth-story window. All were welcomed -- with certain restrictions, of course. There were regular office hours, and the squirrels soon learned not to scratch at the window until given the signal -- stirring within the apartment. Some were bold about walking right into the house, examining the Spruchs' possessions, and burying their nuts under pillows. One categorically refused to leave at closing time, even when rudely chased. Others, more retiring, were content to munch nuts and fruits on the windowsill.Since Spruch is a scientist as well as an animal lover, her observations gain a special force and precision, and she manages to achieve the best kind of popular science writing: scientifically sound, carefully observed, intellectually challenging. Despite our familiarity with squirrels as part of the urban landscape, surprisingly little is known about the habits of these creatures, and Spruch is able to make some interesting contributions to this subject. But most of all, this is a book for animal lovers -- a loving, yet unsentimental account of a fascinating episode in the natural history of a large city.