I strongly second Mike Licona’s book: it’s one of several I would have no problems handing to a non-religious folk anthropology professor (a weirdly specific example, I know, but I have reasons for the example. ) It’s mainly historical analysis of claims of Jesus’ resurrection, but covers the topic in super-depth.
Somewhat related is Gregory Boyd’s Cynic Sage or Son of God?, though that’s more a history of the quest for the historical Jesus up to the mid-90s, and a critical assessment of sceptical methodology up to that time – but including a lot of discussion about why they think they have to go those routes. Easily 1/3 of the book could be lifted directly as-is and republished as a defense in favor of various sceptical approaches, and I’d easily guess more than half the book total could be extracted (with a little more work) for that purpose. It’s moderately out of date now (20ish years later the quest has moved along a lot), but the methodological discussions are still (in my experience) accurate in principle.
Craig Keener is an experienced professor of ancient Greco-Roman history, and also once a staunch atheist. Then he got interested in studying the NT scriptures as key texts from the period which he had been ignoring due to lack of taste for them. Now he’s a Christian and he writes the most detailed historical analyses of the Gospels and Acts currently on the market and up to date. His two-volume set on GosJohn is required reading for that topic (though Craig Blomberg has a much shorter and slightly earlier book covering the same topic); his Historical Jesus of the Gospels dittos for the Synoptics, though he does have a more in-depth (and a bit earlier) analysis of GosMatt, too. His two-volume set on Acts is even more detailed (unsure if the 2nd volume has been released yet); Colin Hemer’s shorter and earlier semi-posthumous work The Book of Acts and its Setting in Hellenistic History is still mostly up-to-date if you’d like an equally professional but far less time-consuming read – it’s practically the modern standard textbook for the practice of histiography on ancient texts. (Keener’s work is an ample and worthy successor, though structured a bit differently.)
I don’t know about Maier’s Marginal Jew series firsthand – I bought most of the series many years ago but haven’t gotten around to reading them yet – but I hear many good things about them. Every time I remember I have them I want to dig them out and finally read the series. Again, historical analysis of the canonical stories of Jesus with lots of sidebar topical digressions.
All the previously mentioned books are written by Christians of one or another flavor, but you won’t find any fundy attitudes or thought processes in them. (To them I could add NT Wright’s series on the NT, Jesus’ life up to the Passion, the Passion, and now I think Paul. I’m less uniformly fond of that series for various reasons, but not because he acts in a fundamentalist manner toward the texts.) They are highly professional works, massively footnoted with commentary and sources. (I must warn you YOU WILL NEVER GET TO THE END OF SPENDING ALL YOUR MONEY ON FASCINATING TOMES UNEARTHED IN THE FOOTNOTES!) The authors know how to bracket out their personal ideological preferences and concentrate on the data neutrally (though Boyd slips into apologist mode a little more than the others occasionally – always in an entertainingly critical way for my taste, but your mileage may vary). They’re hugely charitable to their opponents (even Boyd despite his occasional snippiness), and are clearly well-read in opposing arguments and viewpoints (even ones they regard as near crazy like the Jesus Myth proponents), often positively citing opponents for credit or as authorities. Like Licona’s tome, I would quickly hand any of them to a non-believing secularly trained folk anthropologist professor with an expectation of professional respect (both ways).
Dr. Ehrman’s professional specialty is textual criticism, at which he is no slouch (effectively being Bruce Metzger’s heir in one of the standard reference works on the topic) – but when he lets his ideological preferences (and apparently his love of public attention) get the better of him he can go off the rails and get in trouble. (To be fair, Dr. Metzger had some similar problems occasionally in the other direction.) He’s able to be much more neutrally moderate on the topic when he thinks he’s writing something only scholars are likely to read. He and Daniel Wallace like to spar a lot, mostly over Dr. E’s occasional public abuses of text-critical methodology and conclusions (though they agree on very much more than they disagree concerning that topic). I can point to some books from each of them concerning text-crit if you want; I’m not sure if you were asking about that, but it’s an important topic and one Dr. E is heavily connected to.