Pity the author who decides to write a biography of a senior member of the Communist Party of China. In an organization already legendary for obsessive secrecy, discussing the lives of leaders is a grave taboo. For party insiders, there is almost nothing but downside in speaking with any sort of candor to would-be biographers.

Ezra Vogel, a professor emeritus at Harvard and a longtime East Asia scholar, was evidently aware of the obstacles he faced when he began working on his massive life of Deng Xiaoping a decade ago. The challenge, he writes, was made greater by the fact that by nature and due to early training in the underground movement, Deng was deeply secretive: he memorized everything, leaving "no paper trail." Undeterred, Vogel has gone to enormous lengths to document his subject, devoting the first 14 pages of Deng Xiaoping and the Transformation of China to an exhaustive list of interviewees, memoirs, official papers and other sources consulted. It's impressive, as is the sheer heft of the book's 900-odd pages. If dropped, they would pose a danger to household pets and young children. (See the top 10 political memoirs.)

Vogel's painstaking research provides plenty of fascinating detail. The description of the period after Tiananmen, for example  when the octogenarian was forced to call on a lifetime's accumulated political wiles to defeat an attempt by conservatives to almost completely reverse his reforms  is eye-opening. The pages in which Deng effectively threatens to have then Communist Party Secretary Jiang Zemin dismissed unless he throws his support behind renewing the reform drive are very nearly worth the price of the book alone. Coverage of Deng's foreign policy successes is also readable. Within 15 months of assuming pre-eminent leadership in 1978, he made five tours, restoring fractured relations with Japan, cementing ties with the U.S. and traveling through Southeast Asia to learn from the region's booming economies.

Of course, after those early jaunts Deng never left the country again, for he was above all concerned with a domestic issue: China's modernization. On the ways through which Deng set about the enormous task of rebuilding the gutted economy, shattered by decades of turmoil under Mao Zedong, Vogel is exhaustive. At times, in fact, the huge weight of detail threatens to overwhelm the ordinary reader (witness the seemingly endless analysis of the early political battles Deng fought against party conservatives). Then again, other sections of this enormous tome are maddeningly light on the whys. Beyond some anodyne platitudes about his commitment to the party and to China, we get little sense of what made Deng tick. In particular, we are left wondering how and why this apparatchik and party fixer, who until Mao's death in 1976 appeared largely content to follow his orders, suddenly blossomed into a radical economic reformer. (Read "Thirty Years After Deng: The Man Who Changed China.")

Vogel is curiously reluctant to offer insight into Deng's character. Other biographers would have extracted many psychological nuggets from the fact that, after leaving home at the age of 16, Deng never went back or saw his parents again. But Vogel is happy to see this merely as evidence that Deng "was determined to do what was good for the Party." Thus, despite its great length, Vogel's biography ultimately leaves us hungry for more. And that's just the way the canny Deng  and the cadres who have succeeded him  would want it.

Read TIME's 1986 Man of the Year cover story on Deng Xiaoping.