This is an underground tour of any large city (it happens to be New York) as it was, as it is today, with all that science has contributed to the operation of city life. Plumbing, from the watershed to the faucet, and down the drain again; sewage and its disposal; heat, steam, gas, electricity; communications- from mail chutes to telegraph, telephone; fire alarm call boxes; burglary networks; transportation -- control of traffic lights; the subway systems; all these make up the vast underground machinery, whose invention, functions, maintenance is explained for scientifically- minded youngsters. This book, by the author of Run, Run (Simon & Schuster-1941) was originally scheduled for spring. Being sold for adults as well. Teen age and up.