no other branch of the federal government furnishes employment to so many men as the postal service, particularly that branch of it in which letter carriers and clerks are used. in every city vacancies occur frequently, by reason of death, resignation or transfer, and the prospects of employment are always good for intelligent young men of studious habits. to secure an appointment in the postal service, as in other fields of labor, one must prove his fitness for the job desired. uncle sam requires that this shall be done in an open competitive examination, and usually there are hundreds, in the large cities thousands, competing in the same examinations. taking new york city as an example, the annual appointments to each position average between 200 to 300, while the eligible lists usually contain 1,000 to 1,500 each. from this it will be seen that only a small percentage stand any show of appointment. those that do succeed are the men who took pains to prepare themselves for the test by a careful study of the subjects required. the purpose of this book is to help the candidate to “brush up,” to direct him in self-improvement, and point the way by which any person of ordinary intelligence, willing to devote his leisure moments to study, can pass a good examination and get within striking distance on the eligible list.