In a long interview with a journalist shortly before his death, Zolla teasingly predicted: "It won't be easy to retrace the lives I have lived and the directions of my thought" (Fasoli 2002,p.29). On another occasion, when asked who had been a key figure in his own quest, he replied by quoting two metaphors, both of them aquatic.

The first is from Zolla's collection of essays Che cos'è la tradizione (What is tradition?, 1971), a work that Bernard Wall described as a manifesto of a fearless program of reaction against the spiritual atrophy of modern civilization: "Humans are like carp," wrote Zolla, "who flourish and grow when there is a rock in the center of their pond that they can swim around in harmonious circles" (p.9). The second metaphor, from Zolla's Verità segrete esposte in evidenza (Neglected truth exposed, 1990), is contained in a broader reflection, abbreviated here: "Every life", wrote Zolla, "comprises an invisibile interiority that is substantial to it. The only way to grasp this is to sidestep tangible appearances, to take a leap against the current like the salmon, who is the living symbol of knowledge in the Old Norse Scriptures" (p. 154). The carp circling the rock and the salmon swimming upstreams towards the source – no images could better express the two leading traits in Zolla's intellectual biography and at the same time the character of his peculiar philosophical vision.

Syncretism, which Zolla vigorously defended in his essay "Il sincretismo" (1986), and metaphysical experience, which in the first lines of Archetypes (1981) he described as "the gathering in of the aloof mind" when it "becomes absorbed in its self-existent identity and sameness", were as much leitmotifs in Zolla's pursuit of a unitive knowledge as was his incoercible drive toward the systematic exploration of otherness, a notion that he shaped into an extraordinarily vast array of implications, much beyond its strict ethnological meaning. In a memorable lecture given at the Interreligious Colloquium at the Rothko Chapel in Houston in 1974 (see Ibish and Marculescu, 1978), Zolla described otherness as an antipodal category of the human spirit, the paradigm of an inverted world where ordinary life might flow peacefully between action and contemplation, and the esoteric life as a joyous apprenticeship in metaphysical experience. This broader notion of otherness offers a key to an unbiased investigation of Zolla's accumulated research into alchemy, including Western, Indian, and Daoist traditions; mysticism, which he explored in a monumental anthology of pagan and Christian contemplatives (I mistici dell'Occidente, 1963); archetypes, viewed in the omonymous treatise (Archetypes, London and New York 1981) as the unifying patterns underlying historical processes ; shamanism, particularly in the Native North American and Korean contexts; and tradition and metaphysics, fields par excellence of Zolla's lifelong spiritual quest. His encounters with survivals of the past among the North-American Indians, in Africa (Nubia and Cairo), and especially in the East (Israel, Iran, India, Bali,Taiwan, Korea, and Japan), were analyzed in his quarterly journal Conoscenza religiosa. An international group of leading specialists contributed to its sixty-eight issues.

The most perceptive interpreter of the multifaceted identity of Zolla's spiritual anthropology was probabbly the Romanian historian of religions, Ioan P. Culianu (1950-1991). In his view Zolla was "perhaps the most original,versatile, and untimely of Italy's foremost intellectuals, displaying supreme indifference towards the fashion of the day and therefore – needless to say – controversial" (Culianu,1990,pp.222-224). In his reconstruction of the image of the Indian in American literature, which Zolla made in his celebrated book The Writer and the Shaman (1969), he approached the categories from the point of view of the Native American. Moreover, Culianu emphasized that this process of lucid identification with the indigenous point of view, or with the shaman who effects his ascent to heaven in trance, or with the mystic enraptured in a circle of contemplative bliss, was possible thanks to the new position of the "intelligence out of love" (a fairly faithful translation of Dante's "intelletto d'amore"). To kindle a certain quality of love in the process of comprehending the inner nature of otherness was the esoteric part of Zolla's intellectual achievement. He was well aware that such an achievement could not be pursued except by swimming upstream against the current of his time. No vision could be as antipodal to the spirit of the age which was dominant on the eve of the 1968 student revolts as the one Zolla depicted in Le potenze dell'anima (The powers of the soul, 1968), a crucial investigation of the spiritual morphology in the history of culture.

His rigorous and passionate explorations of these several fields, make Zolla an unusual thinker, and a candidate for a nonparochial reconsideration of his spiritual anthropology. Zolla's work is imbued with the passion for truth that Abraham Joshua Heschel immediately recognized at the time of their first encounter in Rome in the late 1960s. In fact, Zolla was the dedicatee of the Italian edition of Heschel's Passion for Truth (1974).