That book is a bit beyond my budget at the moment, but I may eventually get it.
However, here's something I consider strong evidence that Jesus Christ was largely mythical if not completely mythical: how well he fits Lord Raglan's mythic-hero profile.
I have composed a big list of Lord Raglan evaluations at
List of Lord Raglan evaluations - Atheism, though these are mostly by myself. Other evaluations may differ.
Out of a maximum score of 22, I find a score of 18.5 for the four canonical Gospels taken together, close to what Alan Dundes had found. Treating them separately, I find
Matthew: 19
Mark: 11
Luke: 16
John: 13
Jesus Christ is way up there, alongside Krishna (17), Zeus (14.5 out of 16), Hercules (15), Perseus (17), Oedipus (13), Romulus (19), King Arthur (14.5), etc.
He even scores higher than the Buddha, who scores 13.
Looking at the Old Testament, Moses scores 15, while King David scores 4.
Alexander the Great scores 9, Julius Caesar 9.5 and Augustus Caesar 10, but real people in modern times typically score much less. People like George Washington (6), Napoleon (8), Abraham Lincoln (6), Charles Darwin (5), Winston Churchill (5), Adolf Hitler (4), JFK (7, with controversies about his death, 8), Muammar Khadafy (or any of the numerous other Roman-alphabet spellings of his name, 5.5).
I included MK because he's one of the few notable leaders in recent centuries to have been repudiated by many of his followers late in his career. Richard Nixon and Mikhail Gorbachev may also qualify. RN in the Watergate scandal and MG by the Soviet Union's republics voting the Soviet Union out of existence and him out of a job.
Lord Raglan had neglected to include another criterion: prophecy fulfillment, especially with attempts to thwart it. That's a common Christian apologetic, what prophecies Jesus Christ had fulfilled, but Jesus Christ was far from alone in fulfilling prophecies. Krishna, the Buddha, Zeus, Oedipus, Perseus, Romulus, King Arthur, even some historical people like Alexander the Great and Augustus Caesar.