In the Jewish canon the books of Ezra and Nehemiah originally constituted one book. It is the opinion of modern scholars that both books were put into their present form by one and the same editor. The period covered by the book of Nehemiah is the years 445-432 B.C. It is based upon the genuine memoirs of Nehemiah, but also, according to the critical view, contains much extraneous material, the memoirs having been freely used by compilers whose aim it was to prove that the work of restoration of the temple, the cult, and the general reorganization was performed by Babylonian Jews who returned from the exile; whereas, as a matter of fact, much of the work was due to the section of the Jewish community of Jerusalem which had remained in the country. . . . Nehemiah's sorrow over the desolation of Jerusalem is depicted, and he prays to God for opportunity to rebuild the city. Permission is granted him by the King to undertake the work; he arrives at Jerusalem, surveys the ruins, and begins to rebuild the walls. . . .
As to how much of the book represents Nehemiah's memoirs, scholars are not agreed. The genuine historical basis of the work is probably the account of Nehemiah's first visit, his activity in the rebuilding of the walls, his return to Persia, and his subsequent second visit to Jerusalem.
—From "The New International Encyclopedia."