I’m a U.S. historian who would love to learn more about the medieval world. Do you have any book recommendations that combine readability and scholarship? (Pardon me if you’ve done this before, but I can’t seem to locate the post.)

Some of the big universities and presses do good introductory texts: Routledge has a series of Handbooks and Companion texts on both general (The Routledge Companion to Medieval Europe) and specific (The Routledge Companion to Medieval Iconography, the Routledge Handbook of Identity and the Environment in the Classical and Medieval Worlds) topics. Oxford University and Cambridge University also have some good Handbooks, Companions, and Histories, and Historical Encylopedias and Dictionaries. 

Then I would recommend pillaging their citations for important monographs in fields that you’re interested in.