Brenda Maddox’s “Freud’s Wizard: Ernest Jones and the Transformation of Psychoanalysis” (Da Capo Press, 354 pages, $26) poses a fundamental question about biography: To what extent do ideas, or, more specifically, the spread of ideas, depend on personalities? Freud himself wondered whether or not his new “science” of psychoanalysis would travel beyond turn-of-the century Vienna, Austria, and become something more than an exclusively Jewish enterprise.

At first Carl Jung seemed to be the gentile vehicle for Freudian ideas, but he became a rival. Ernest Jones, a Celtic Welshman turned Anglophile, proved an antidote to renegades such as Jung who broke out of Freud’s tight circle and sought to establish their own therapeutic regimes.

Jones was a kind of wizard (his mother had wanted to name him Merlin). He was a good mobilizer with a knack for establishing organizations that furthered Freudian ideas. He wrote in an accessible style that enticed influential readers — his book on Hamlet and Oedipus impressed both James Joyce and Laurence Olivier.

But Jones was not merely a popularizer. He had a magnetic personality that attracted women. He courted Freud’s daughter, Anna, and though his suit was not successful, it demonstrated how powerfully he wished to impose his personality on Freud’s movement as well as his intimates. Jones’s erotic adventures often got him into trouble, but Freud understood that Jones was the indispensable disciple, worth any amount of trouble.

Jones repaid his mentor’s trust during Freud’s moment of peril in Vienna. Ms. Maddox begins her biography by tersely evoking Jones’s mission in March 1938 to save the founder of psychoanalysis. Hitler had entered Vienna the day before. His views of psychoanalysis as a Jewish virus were well known. Jones understood that if Freud did not leave Vienna he might well be murdered. Commercial flights to Vienna from London had been canceled. The enterprising Jones hired a private plane and managed to enter the city, only to be arrested. Fluent in German, he talked his way out of incarceration. It took him nearly a week to convince Freud to abandon the city that meant everything to him.

Freud did not relent until Jones promised to spirit his master’s immediate family and associates out of Nazi-occupied Vienna. Not only did Jones succeed in this daunting task, he got the British government to approve work permits for these refugees at a time when public opinion in Britain was opposed to exiles whose arrival increased competition for precious jobs.

Where did Jones get his chutzpah? He liked to joke that he was a “Shabbes-Goy” who does the work Jews are not allowed to perform on the Sabbath.” Jones had grown up in Wales at a time when a bright boy yearned to assimilate into British culture. Yet he never lost his Welsh character, a feistiness he shared with his hard-working father.

Jones rejected a place at Oxford for medical studies in London and Cardiff, Wales. Interested in brain neurology, Jones found Freud’s ideas captivating and adapted them to his own purposes. That Jones became Freud’s biographer, writing an elegant three-volume biography, seems inevitable in retrospect. The Freud biography perfectly expressed Jones’s desire to honor his master even as Jones advanced his own life’s work.

Jones’s story, Ms. Maddox notes, has been told before by Jones’s friend Vincent Brome, and she might have added another word or two about her predecessor, an author of several biographies to whom many of us are deeply indebted. But Ms. Maddox is right that much new material has appeared since Brome published his biography in 1982, and she pays handsome tribute to the scholars who have enriched her work.

Ms. Maddox herself has a special place among current biographers. She has a knack for picking figures like Nora Joyce, for example, who are slightly off-center, but without whose presence the story of a James Joyce or a Sigmund Freud would be immeasurably diminished. Her approach to biography did not seem essential when she first began work on Nora Joyce. Richard Ellmann, the distinguished Joyce biographer, doubted Ms. Maddox would have enough material for a full-scale biography. But Ellmann acknowledged that Ms. Maddox had proved him wrong.

While Ms. Maddox does not face the same skepticism with “Freud’s Wizard,” it is important to realize how her work has re-centered the enterprise of biography, broadening and deepening its reach into the panoply of personalities that surround and sustain the Freuds and Joyces who once seemed a force unto themselves.

crollyson@nysun.com