Michael Lavigne’s ambitious first novel, “Not Me,” is an apparently light and easy read about a topic that could hardly be more difficult and disturbing: Could a Nazi be a Jew; a Jew, a Nazi? (Oh, would that a Nazi did ponder this!) Or are there good guys and bad guys, where bad guys are evil at the core — irredeemable monsters essentially unlike the rest of us?

“Not Me” is well-structured and suspenseful, moving from subplot to subplot and character to character with some neat tie-ins. Set in a retirement community in Florida and narrated by midlevel standup comic Michael Rose, the story alternates between Michael’s nice bits of prose and humor — ruminations on his failed marriage, his weaknesses as a father, the scene at the hospital where his father is dying — and entries from the journal his father has just given him.

According to this journal, Michael’s dad — award-winning community Jew and professional macher Heshel Rosenheim — is a self-created fiction. He is really Heinrich, a Nazi concentration camp accountant who assumed a Jewish identity in time for liberation and found himself in pre-state Israel fighting the Israeli War of Independence. His feelings continually flip-flop until he finally embraces his identity as Heshel the Jew.

Lavigne, who is a San Francisco resident and a member of Congregation Emanu-El, has used excellent source material in constructing vivid journal entries from the Yishuv. Few lines carry more passion and conviction than this from a survivor confronting Heshel-née-Heinrich:

“Oh yes — and at the glorious battle of Deir Yassin — where we lost more than they did — attacked on every side! — gunmen hiding behind children, women firing from beneath their burkas … But you — you could see only their suffering and not ours.”

But rather than a penetrating analysis of the Nazi heart and soul, Lavigne offers us existentialism. Here, character is not destiny; the self is mutable. There is only “choose life.” “Like everybody else,” says Heshel, “I was on my own side.”

It is not clear how or why this German bookkeeper suddenly becomes “strong and brave,” “good with a weapon” and with “the clear head of a leader,” or why everyone admired him on the kibbutz. But the author does show us how the former Nazi becomes a Jew, and how identity itself is created: through action.

Not only Heshel’s experiences but his actions as a Jew formed him. Voila! A new self is created, and eventually Heshel is shocked to find himself thinking in Hebrew.

Michael evinces little more compassion for the people around him than Heinrich did for the suffering Jews. He toys with ideas such as the intimate relationship between Jews and Germans, why they hate us, how to remember the Holocaust yet “let it go.”

But as a comic, “What he sees is emptiness, vacuity, folly. And what is the ultimate folly? To look out into the vastness of the universe and somehow conclude that your life means something, in fact, that anything means anything at all.” He is “always go, go, going … Looking everywhere. Never finding.” He doesn’t know “how to be.”

Lavigne presents some amalgamated Christian theories — that pain and loss create the capacity for love and that suffering and humiliation temper the soul into angelhood. But his conclusion derives from the Jewish fountainhead: tshuvah is always available to a person and “the blessings of his deeds would live on for generations.”

In his examination of identity, Lavigne raises issues ranging from adoption to Zionism, euthanasia to ennui. Despite its beguiling wit and peculiar lack of passion, this remarkably original novel was no doubt written in anguish in order to process the Holocaust and share some thoughts — many of them very interesting and painfully honest.

“Not Me” by Michael Lavigne (320 pages, Random House, $34.95).

Michael Lavigne will be appearing 7:30 p.m. Tuesday, Nov. 22 at the Bureau of Jewish Education community library, 1835 Ellis St., S.F. Information: (415) 567-3327 ext. 704.