Experts, insists Mr. Golde, in this firm and cautionary guide, are set upon this earth to work for you, not you for them. Therefore when confronting the formidable fortifications of doctors, lawyers, or stock market oracles--and others--a rationale for evaluating your expert is of prime importance. Mr. Golde lays down specifics for expert-appraisal in three prime fields--medicine, law and Wall St.--suggesting methods for selection and for investigation of background and practice. In the medical section (could be read with Blum's The Commonsense Guide to Doctors, Hospitals and Medical Care--1964 for top value) a rated list of major hospitals is included. Mr. Golde also dispenses some bitter pills for the investor: ""In general stockbrokers tend to be the least valuable source of professional investment advice available."" The best bet is the investment advisor and the best of them usually will not handle any account under $100,000. Extreme caution is the word. The section on lawyers, while undoubtedly not complete, goes far to untangle legal barbed wire. Throughout the emphasis is on evaluation by intelligent observation, interviews and some essential knowledge. Although some experts tend to be huffy about such tender matters as their august qualifications, Mr. Golde asserts that laymen have a right to cast a beady eye. Most useful.