Impelled solely by an enthusiastic love of Nature, and neither asking nor receiving outside aid, these early workers opened the way and initiated the movement through which American science has reached its present commanding position. This book gives some account of these men, their early struggles, their scientific labors, and, whenever possible, something of their personal characteristics. This information, often very difficult to obtain, has been collected from a great variety of sources, with the utmost care to secure accuracy. It is presented in a series of sketches, some fifty in all, each with a single exception accompanied with a well-authenticated portrait. "Fills a place that needed filling, and is likely to be widely read."--_N.Y. Sun_. "It is certainly a useful and convenient volume, and readable too, if we judge correctly of the degree of accuracy of the whole by critical examination of those cases in which our own knowledge enables us to form an opinion.... In general, it seems to us that the handy volume is specially to be commended for setting in just historical perspective many of the earlier scientists who are neither very generally nor very well known."--_New York Evening Post_. "A wonderfully interesting volume. Many a young man will find it fascinating. The compilation of the book is a work well done, well worth the doing."--_Philadelphia Press_. "One of the most valuable books which we have received."--_Boston Advertiser_. "A book of no little educational value.... An extremely valuable work of reference."--_Boston Beacon_. "A valuable handbook for those whose work runs on these same lines, and is likely to prove of lasting interest to those for whom '_les documents humain_' are second only to history in importance--nay, are a vital part of history."--_Boston Transcript_. "A biographical history of science in America, noteworthy for its completeness and scope.... All of the sketches are excellently prepared and unusually interesting."--_Chicago Record_. "One of the most valuable contributions to American literature recently made.... The pleasing style in which these sketches are written, the plans taken to secure accuracy, and the information conveyed, combine to give them great value and interest. No better or more inspiring reading could be placed in the hands of an intelligent and aspiring young man."--_New York Christian Work_. "A book whose interest and value are not for to-day or to-morrow, but for indefinite time."--_Rochester Herald_.