Here are three types of underground transits described in absorbing detail. In New York, besides the subways, there is a cross sectioning of many more of the city's myriad tubes- for steam, sewage, mail and so forth. Under the Hudson the tunnels to New Jersey are accounted for in their present operation and the complications of their construction. And in Europe and the wide world there are the metros, undergrounds, Alpine tunnels etc., without which we could not get from one place to another quite as easily as we do.