Who is this person?

[Eva Elisabeth]

Hint #3: He worried about a security issue.

[Eva Elisabeth]

Hint #4: He worried about Abraham Lincoln's security on the way to the first inauguration.

[RJNorton]

Samuel M. Felton?

http://www.smithsonianmag.com/history/th...56/?no-ist

[Eva Elisabeth]

Very good, Roger, that is correct! Thanks for guessing again. This is the book Gene recommended (thanks, Gene!):
http://rogerjnorton.com/LincolnDiscussio...-1502.html

[Eva Elisabeth]

This lady was allegedly the first to approach and warn Felton about a possible plot in Baltimore. Who is she?
   

[RJNorton]

Kate Warne?

[Eva Elisabeth]

Good guess, Roger, but it's not Kate Warne.

Hint #1: Almost exactly one year later, Abraham Lincoln consulted her in a family matter.

[Eva Elisabeth]

Hint #2: A. Lincoln seeked her advice after Willie's death.

[L Verge]

I don't know about the Baltimore Plot warning or assistance to Mr Lincoln, but the photo is of Dorothea Dix.

[Eva Elisabeth]

Brilliant, Laurie. During the CW, she was Superintendent of Army Nurses, and A. Lincoln asked her to recommend a nurse to care for Tad. Her advice was to employ Rebecca Pomroy.

[Eva Elisabeth]

Two further recent posts made me think of this gentleman. Who is he?
   

[RJNorton]

King Mongkut (Siam).

[Eva Elisabeth]

Sorry for delay. Kudos, Roger, INCREDIBLE! I thought this one would need a while!
When reading about the many horses and mules that served and died in the CW, I was reminded of Hannibal's elephants ("only" about 40 though) in the Second Punic War that died from the cold weather when crossing the Alps, and thought that Hannibal would probably not have rejected the King of Siam's present.

[RJNorton]

Who is this man?

Hint #1: His name usually appears in books because of a book, but he was not an author.

[J. Beckert]

Josiah Crawford?