"An Undivided Union" is the sixth and last volume of the "Blue and Gray—On Land" series. Like its predecessors it relates the adventures of the Riverlawn Cavalry, a Union regiment, raised in Kentucky, and participating in the daring campaigns undertaken by the Army of the Cumberland. The fifth volume of the series left the regiment at Murfreesboro, after most gallant service performed at the battle of Stone River; in the present book is given an account of the operations around Murfreesboro, before Tullahoma, and through the bloody battles of Chickamauga, Chattanooga, Lookout Mountain, Missionary Ridge, and other contests leading up to Sherman's famous March to the Sea.

As in the other stories of this series, Deck Lyon has again come to the front as a daring hero, but his achievements are closely seconded by his foster brother, Artie, and by the firm friend of the two, Captain Life Knox. If Deck does some smart things, it must be remembered that he was a smart young man or he would not have risen to be senior major, first battalion, of the Riverlawns. Besides this, the major still had with him his famous charger, Ceph, a steed with almost human intelligence on certain points, and one that had helped him to escape from many a perilous position.

In the completion of this work some thirty authorities have been consulted, including the Government Records, records of the Army of the Cumberland, and biographies of the principal generals on both sides who took part in the various operations. Thus the book has been made, from an historical standpoint, as accurate as possible. It may be that errors have crept in, but if so it is hoped that they will not be of sufficient importance to mar the general usefulness of the volume, outside of its value as a bit of fiction.