Through Two Doors at Once

The intellectual adventure story of the "double-slit" experiment, showing how a sunbeam split into two paths first challenged our understanding of light and then the nature of reality itself--and continues to almost two hundred years later.

Many of science's greatest minds have grappled with the simple yet elusive "double-slit" experiment. Thomas Young devised it in the early 1800s to show that light behaves like a wave, and in doing so opposed Isaac Newton. Nearly a century later, Albert Einstein showed that light comes in quanta, or particles, and the experiment became key to a fierce debate between Einstein and Niels Bohr over the nature of reality. Richard Feynman held that the double slit embodies the central mystery of the quantum world. Decade after decade, hypothesis after hypothesis, scientists have returned to this ingenious experiment to help them answer deeper and deeper questions about the fabric of the universe.

How can a single particle behave both like a particle and a wave? Does a particle exist before we look at it, or does the very act of looking create reality? Are there hidden aspects to reality missing from the orthodox view of quantum physics? Is there a place where the quantum world ends and the familiar classical world of our daily lives begins, and if so, can we find it? And if there's no such place, then does the universe split into two each time a particle goes through the double slit?

With his extraordinarily gifted eloquence, Anil Ananthaswamy travels around the world and through history, down to the smallest scales of physical reality we have yet fathomed. Through Two Doors at Once is the most fantastic voyage you can take.

Standard and Primary covers are widely available through general retailers. They often have higher print runs and can be cheaper, especially during sales.

In contrast, Direct Market (DM) and variant covers are primarily sold in comic shops. DM editions tend to have more limited availability and may be more valuable to collectors.

The main differences lie in artwork style, availability, price, and collector appeal. Ultimately, the choice between standard and variant covers depends on personal preference, budget, and individual collecting goals.

Comic book enthusiasts have various formats to choose from when collecting their favorite stories.
Here's a brief overview of the main types:

Omnibus

• Large, hardcover collections
• Usually contain complete runs or extensive story arcs
• Typically 800-1000+ pages
• Higher price point, often €100-€150

Oversized Hardcover (OHC)

• Similar dimensions to omnibus, but thinner
• Collect shorter runs or story arcs
• Usually 300-600 pages
• Priced between €30-€50

Hardcover (HC)

• Standard-sized hardcover books
• Collect 6-12 issues typically
• Similar dimensions to single issues, but with a hard cover
• Priced around €25-€35

Trade Paperback (TP)

• Softcover collections
• Standard comic book size
• Usually collect 4-6 issues
• Most affordable option, typically €15-€25

Other Formats

• Absolute Editions: Oversized, deluxe hardcovers (mainly DC Comics)
• Compendiums: Massive paperback collections
• Graphic Novels (OGN/GN): Original stories not previously released as single issues

The choice between these formats often depends on personal preference, budget, and collecting goals. Omnibus and OHC editions offer larger artwork and more content but at a higher price, while TPs provide a more affordable way to collect complete story arcs