You can learn the bare basics of Rabbi Abraham Isaac Kook’s life just from reading the jacket of Yehudah Mirsky’s biography, “Rav Kook: Mystic in a Time of Revolution,” published in 2014 by Yale University Press.

Born in 1865. Died in 1935. First chief rabbi of Jewish Palestine and founder of religious Zionism. Profoundly original thinker.

Here are the basics of Yehudah Mirsky’s biography: Born in 1961 and raised in a modern Orthodox home in Manhattan’s Upper West Side. Undergraduate degree from Yeshiva College, where his father, a rabbi, also was an English professor and dean. Earned a law degree from Yale and went to Washington, first working as a congressional aide and then in the State Department during the Clinton administration. Earned a doctorate in religion at Harvard and then made aliyah; his initial focus on learning Arabic and studying politics shifted into a dissertation on Rabbi Kook, which focused on the rabbi’s early years, before Kook moved to Israel. And then his academic interest in Rav Kook — as Rabbi Kook is known — became the seed of the popular biography in Yale University Press’ Jewish Lives series, and his academic career moved him back to the United States. He now lives in Brookline, Mass.; he’s a professor of Jewish and Israel studies at Brandeis. And he is revising his dissertation into another book.

Dr. Mirsky first encountered Rav Kook’s work when he was in Israel, studying at Yeshivat Har Etzion. It was a different world from America in many ways — and it turned out that Dr. Mirsky needed a different religious hero than Yeshiva University’s Rav, Rabbi Joseph B. Soloveitchik.

He found that hero in Rav Kook, who, as Dr. Mirsky wrote recently, “told you that your very stirrings for justice beyond the law, for beauty, for longing and religion without answers; your wanting to keep faith with your doubts and confusions; your seeing yourself not just as Jewish but as human; your desire to see God not as rejecting but as coming out of the travails of your own soul — that all that was itself what made you a good Jew.”

It was a perspective that stayed with Dr. Mirsky in the decades that followed his time at Har Etzion.

“I felt very Kookian in the State Department,” Dr. Mirsky said in a recent interview. “For Rav Kook, working for a universalist kind of ethics is not at all contradictory to being a religious Jew. In the State Department, you’re trying to advance a certain ethical ideal you think is good for all mankind. I felt that very strongly when I was there.”

Dr. Mirsky recalled a story from his time at yeshiva in Israel.

“Menachem Begin was taking in all these boat people” — 360 Vietnamese refugees to whom the prime minister gave Israeli citizenship as his first act on assuming office.

“Someone in the yeshiva was collecting money for them. Some of the teachers were upset that they were collecting for these Buddhists. Rabbi Lichtenstein” — the co-head of the yeshiva, and Rabbi Soloveitchik’s son-in-law — “said that even if nobody else cared about the boat people, who else but b’nei Torah” — Torah students — “should care about people who are suffering.

“What’s so sad in contemporary Orthodoxy is that this a revelation,” he said. “Rav Kook decried that. There’s a passage that I always come back to, that he wrote in 1920 or so, that modernity has divided everything into separate camps. I think that’s very true.”

Dr. Mirsky is the sort of professor who thinks, and writes, about the nature of modernity and about political camps, about divisions in American political life and within his own religious community.

Dr. Mirsky said that religious Zionism — the world of Rav Kook — and modern Orthodoxy — the world of Rabbi Soloveitchik — “are two different entities. American Jews regularly blur the lines, because they’re living in both, but they’re different movements, responding to different challenges, with different traditions and cultural heroes. One of the things going on with my book is I’m introducing American readers to a lot of the history, concepts, culture, and sensibilities of some basic issues in religious Zionism.”

He credits Yeshiva Har Etzion’s co-leader, Rabbi Yehudah Amital, for introducing him to Rav Kook. “He was an apostle of Rav Kook in his own way.

“All the things you think make you a bad Jew — like learning Torah but being interested in other things — they’re a part of you,” Dr. Mirsky said. “Rav Kook says that’s what make you a good Jew, if you do it authentically and are willing to live your commitments.”

In formulating religious Zionism, Rav Kook broke with most other Orthodox rabbis, who saw nothing but evil in the early Zionist pioneers, with their atheism, their Sabbath desecration, and their belief that their labor rather than God would save the Jewish people.

“A central aspect of his tolerance was that the people he disagreed with, who he made a very concerted effort to honor and respect, were people who weren’t just saying things but living out their commitments, including commitments to Jewish physical and cultural survival,” Dr. Mirsky said.

“That’s a larger point worth remembering. If we look at pre-Holocaust Jewish arguments over Zionism in all their permutations, the arguments are incredibly bitter. One thing all the different sides share is they are all profoundly committed to Jewish survival. The discussions and arguments about Israel from some quarters nowadays don’t have that flavor. The arguments from the far left, or arguments from the far right — they are so dismissive of everyone who disagrees with them that there is some absence of a sense of clal Yisrael, Jewish peoplehood, as well.”

One important difference between rabbis Soloveitchik and Kook is their mode of expression. Rabbi Soloveitchik communicated in public lectures, Talmud classrooms, and carefully crafted and polished writings. Rabbi Kook kept a spiritual diary, and his most popular published works were extracted and edited from those diaries by students.

“It’s such a rarity to have mystical diaries in the Jewish tradition,” Dr. Mirsky said. “Maybe because the tradition is so commentarial. He was trying to register what was going through his mind. He started keeping them in the 1890s,” the decade before he immigrated to Palestine in 1904.

“He was always a very feeling person. The death of his first wife in 1888 was very consequential for him. It was something of a chastening experience. It made him more introspective.

“Now that we have his diaries closer to their original form, it’s incredible to see what a good job his editors did, what a sprawling mass of texts they had facing them, from which they were able to wrest some kind of order and structure and procession of ideas,” he said.

“It sometimes strikes me as ironic that here I am in my mid-50s, still trying to figure out what Rav Kook was thinking when he was 26,” Dr. Mirsky said.

For the biography, which won the Choice Award and was runner-up for the Sami Rohr Prize for Jewish Literature, Dr. Mirsky summarized Rabbi Kook’s first 39 years in the Russian provinces that are now Lithuania and Latvia in 20 pages. The dissertation, which is devoted to that period of Rabbi Kook’s life, clocked in at 420 pages.

“Almost no one had paid sustained scholarly attention to Rav Kook before he came on aliyah,” Dr. Mirsky said. “For people who are interested in Zionism, the life before eretz Yisrael is less compelling. Indeed, his later, mature writings are incomparably more stirring and dramatic and audacious. A lot of his early writings were in print but no one was bothering to read them. A book I found immensely helpful for organizing the larger idea was ‘Sources of the Self: The Making of the Modern Identity’ by Harvard philosopher Charles Taylor.

“Taylor traces the movement from a sort of rationalist and enlightenment mindset to the modern mindset that is distinguished by expressivism and subjectivity, by people finding the truth within themselves. As I was reading more and more of Rav Kook’s early writings, I could see he was living out this paradigm.

“The big change in his thought when he came to the land of Israel is in the direction of one’s relationship with God. In the early period it is top-down. There’s a sort of divine truth that is outside of oneself. As he moves forward it’s from the bottom up. It becomes a divine truth that is within oneself, within a collective self, within people and society, that is seeking to be expressed. It’s a subtle shift but very powerful. It makes for a more immanent religious experience. It enables a theology of culture, where things like arts and building concrete social political institutions are how God is working through the world, the working out of a desire of something greater than oneself.

“It’s very radical,” he said.

Dr. Mirsky believes that a biographical fact key to understanding Rav Kook is that he was born into what constituted a mixed marriage among Orthodox Russian Jews in the 19th century.

“His mother was from a family of Chabad chasidim. His father was from a family of mitnagdim,” opponents of the chasidim. “Maintaining that duality, and dualities in general, is central to his whole life. At every step of the way he is the person of the holy and the secular, the structure and the anti-structure, the sage and the prophet. He has deep sympathy to new currents and is very traditional in other ways. He develops this complex dialectical way of looking at the world.

“I think he first develops the dialectic as a way to think about himself, how he is drawn simultaneously to talmudic legal study and to more mythic and theological passages. He is helped here by the kabbalah. Kabbalah’s mutifaceted divinity becomes for him the world of differences, a world tied to the deep underlying world of sefirot, which contend with each other but hold each other in balance.”

So what concrete messages should we take from Rav Kook right now?

“We’re living in an age of anger,” Dr. Mirsky said. “Anger is driving people more than ideology and more than their interests. Rav Kook is all about trying to conquer your anger.

“Rav Kook said that anger is a sign of emptiness. Whenever there’s a group full of anger, you know that internally they have nothing.

“There’s a difference between a rage against injustice and anger that’s simply a hatred of other groups. I can understand that someone who has been genuinely victimized is angry, but does he want to take his anger out on something, or does he try to build something?”

“Part of what’s so powerful about Rav Kook is that he placed himself in the middle of incredibly stormy controversies, between religionists and secularists, between right-wing Zionists and left-wing Zionists. I don’t know how he had the courage. The charedim fought him. A lot of the secular Zionists resented him. But he placed himself into this. He worked on the assumption that these people aren’t evil, that there are things that are motiving them, and maybe there are ways one can think this through. He has a lot of faith in God.

“It’s something people should think about. When you’re posting on Facebook or when you’re tweeting, it’s a word you’re sending out and it should be meaningful.

“It should be trying to help, whether to provide direct immediate aid and comfort to someone or just to advance ideas in a constructive way.”