Columbus by Ingri and Edgar Parin D'Aulaire

Full page detailed illustrations in an over-sized picture book
My nine year old read this book to himself to support our study of Christopher Columbus.
The authors share about his boyhood all the way to his life after sailing the oceans.  They handle his faults well yet do not malign him.
-Borrowed from the library.

Alec Flint Super Sleuth The Nina, the Pinta and the Vanishing Treasure by Jill Santopolo*

Fourth grader, Alec Flint, wants to be a detective and has the opportunity as he watches his father (a police officer) solve a Columbus museum case.  Alec needs a sleuthing partner and befriends a new girl Gina.  She proves to be an asset.
Together they figure out who the "perp" is.  Enough clues along the way that the reader can solve the mystery with Alec and Gina.
Points to discuss: lying/half truths; snooping in private property (but they did get in trouble for it)
*Highly recommend.
There is a second book in the series but I could not find any more titles.