The library has acquired reproductions in paper and on microfilm materials for prominent scientists. To determine if the library has sources for the scientist you are interested in try a keyword search in The CAT using the name of the scientist combined with one of the following terms: Letters, Papers, Sources, Correspondence, Diary/Diaries, Archives.
Many papers and other primary sources have not been published and can only be accessed at the library or archive holding the original documents. To identify libraries that may have items of interest consult the following:
You can find documents (primarily published texts) for some scientists online. For example:
The easiest way to locate a biography of a scientist is to do a Subject [Advanced] search in The CAT. Enter the name of the scientist as the subject. For autobiographies do an Author search.
Unfortunately the above approach only works if the entire book is about the one individual. Many people are not famous enough to have entire books devoted to them (or you may not want to read an entire book!) In these cases your best bet is to consult a biographical dictionary or encyclopedia. Typically these sources provide a brief essay (a paragraph to a few pages) summarizing the individual's major accomplishments. The library has hundreds, if not thousands, of these sources. The ones below will get you started.