Traversing a wide range of knowledge, Gravity's Rainbow crosses boundaries between high and low culture, between literary propriety and profanity, and between science and speculative metaphysics.

Part 4 begins shortly after August 6, 1945, and covers the period up to September 14 of that same year; the day of the Exaltation of the Holy Cross, with extended analepses to Easter/April Fool's weekend of 1945 and culminating in a prolepsis to 1970.

Pirate's associate Teddy Bloat photographs a map depicting the sexual encounters of U.S. Army Lt. Tyrone Slothrop, an employee of a fictional technical intelligence unit, ACHTUNG.

Employees of a fictional top secret psychological warfare agency called PISCES, headquartered at a former insane asylum known as "The White Visitation", investigate Slothrop's map of his presumed sexual encounters in London, finding that each location appears to precede a V-2 rocket strike in the same place by several days.

References here include "Red, the Negro shoeshine boy", who will much later be known as the Black Power leader Malcolm X, and jazz saxophonist Charlie "Yardbird" Parker, both of whom represent a threat to white racism.

Katje, on the other hand, will come under Pointsman's control in England, while, as the Christmas season ends, Roger Mexico worries about losing Jessica Swanlake to her other, bureaucratic and sedate, boyfriend, Jeremy (also referred to as "Beaver" because of his beard).

The unit's nominal commander, Brigadier General Ernest Pudding, who is haunted by his traumatic memories of World War I, is brought to (literal) submission through sado-masochistic rituals with Katje, engineered by Pointsman.

With papers identifying him as former German film star Max Schlepzig in Berlin, Slothrop adopts an operatic Viking costume with the horns removed from the helmet, making it look like a rocket nose-cone and is given the name "Rocketman".

Slothrop also comes to meet Gerhardt von Göll, a megalomaniac German director who had previously been seen in Britain, directing a fake propaganda film featuring Black soldiers in Germany.

In the longest episode of the book, we learn more of the history of Franz Pökler, who fathered a child, Ilse, with his wife Leni after being aroused by Greta's image in an erotic scene in Alpdrücken, von Göll's "masterpiece".

Margherita spent many days in a mysterious and ambiguously described factory, where she was clothed in an outfit made from the "erotic" plastic Imipolex G. Slothrop falls overboard and is rescued by black marketeers heading towards Peenemünde, the test site for the V-2 rocket, now occupied by Soviet forces.

He continues his pilgrimage through northern Germany, having changed clothing with Tchitcherine, arriving at Lüneberg Heath and the town of Cuxhaven, also sites of tests and launches by Allied forces of captured V-2 rockets.

A long digression gives the story of "Byron the Bulb", a sentient, seemingly immortal lightbulb whose existence links with Dr. Jamf and his experiments and to the integration of power companies and their Grid to the network of cartels.

Such incidents may be products of Slothrop's finally collapsed mind; or of the increasingly chaotic state of affairs outside the realm of a rising technological class and society that comes to be labeled the "Raketen-Stadt" (Rocket-State) of the future.

Invited to a dinner at the home of a German industrialist, Roger and Pig Bodine manage to escape with the help of some disgusting culinary repartee, but it becomes increasingly clear that the Counterforce does not have the capacity to counter the emerging Rocket State, in part because "the Man has a branch office in each of our brains".

The final identification of Slothrop of any certainty is his picture on the cover of an album by obscure English band "The Fool" (another allusion to Tarot, which becomes increasingly significant), where he is credited as playing the harmonica and kazoo.

The hundred pages or so of the novel include titled vignettes that summarize events in Slothrop's home town of Mingeborough; offer a (self-referential) reading of the Tarot cards for Weismann/Blicero, who also prepares for a final launch of the 00000 rocket with Gottfried in the nosecone; describe failed last-minute non-rescues by popular culture heroes; and allude to the Sacrifice of Isaac and the mythical figures of Apollo and Orpheus.

Both actors played personifications of Death, in Ingmar Bergman's The Seventh Seal and Jean Cocteau's Orpheus, respectively, overt examples of several possible references in the novel to European modernist cinema.

Poet L. E. Sissman, in his Gravity's Rainbow review for The New Yorker, said of Pynchon: "He is almost a mathematician of prose, who calculates the least and the greatest stress each word and line, each pun and ambiguity, can bear, and applies his knowledge accordingly and virtually without lapses, though he takes many scary, bracing linguistic risks.

[15] The recurring themes throughout the plot are the V-2 rocket, interplay between free will and Calvinistic predestination, breaking the cycle of nature, behavioral psychology, sexuality, paranoia and conspiracy theories such as the Phoebus cartel and the Illuminati.

The narrative contains numerous descriptions of illicit sexual encounters and drug use by the main characters and supporting cast, sandwiched between dense dialogues or reveries on historic, artistic, scientific, or philosophical subjects, interspersed with whimsical nonsense-poems and allusions to obscure facets of 1940s pop culture.

Immersing himself in 'the destructive element' and exploring paranoia, entropy and the love of death as primary forces in the history of our time, Pynchon establishes his imaginative continuity with the great modernist writers of the early years of this century."

Locke noted that "Pynchon is obviously capable of the most intricate literary structures—plots and counterplots and symbols that twist and tangle in time and space", but was less impressed by the novel's form: "the structure is strained beyond the breaking point.

Reading it is often profoundly exasperating; the book is too long and dense; despite the cornucopia of brilliant details and grand themes, one's dominant feelings in the last one to two hundred pages are a mounting restlessness, fatigue and frustration.

His genius resides in his capacity to see, to see feelingly, how these various perspectives, apparently so diverse and chaotic, are begotten of the same technology, the same supportive structures that have foundations in the theology of the seventeenth century and the science of the nineteenth."

In 1998, Jonathan Lethem suggested that the novel's failure to win the award stands as "a hidden tombstone marking the death of the hope that [science fiction] was about to merge with the mainstream.

American progressive rock group Coheed and Cambria's song "Gravity's Union", from their science fiction concept album The Afterman: Descension (2013), is named in honor of the novel.

Canadian experimental rock group Rei dos Leitoes's song "Silent on the Island" (2010) incorporates themes from Gravity's Rainbow in its second and fourth Verse passages.

The piece includes palm trees, shoes, stuffed toys, a lemon meringue pie, Richard Nixon, Sigmund Freud, an iron toad wired to an electric battery, a dominatrix, and other images from the novel.

[43] In 1999 a painting by the American artist Fred Tomaselli, inspired by the novel and titled Gravity's Rainbow (Large), was added to the permanent collection at the Whitney Museum of Art in New York City.