Unless you are a specialist or watch a lot of obscure YouTube videos you have probably never
heard of He II or superfluid helium. This substance a unique liquid form of the element helium
is produced and used in multi-ton quantities to enable much of modern science. Altogether He
II is at the heart of more than a dozen large scale scientific facilities world-wide
representing an investment of tens of billions of dollars. It cools the magnets and cavities
that contain and accelerate the particle beams at the Large Hadron Collider and is also used in
accelerators for the study of rare isotopes and nuclear astrophysics. This little known liquid
is in reality one of the enabling technologies of the future. A manifestation of quantum
mechanics He II exhibits amazing behaviors. It can flow up the side of a container against
gravity it can move through small openings without friction and it can transfer heat
extremely efficiently via a mechanism not seen elsewhere in nature. This book tells the story
of He II. It describes the discovery of the fluid the observation and understanding of its
behavior the development of underlying theory and the evolution of He II from a laboratory
curiosity to an industrial-scale coolant. The current and possible future applications of He II
are described. Like all science and engineering the story of He II is a human story and the
role that personalities politics communication cooperation and competition play in the
development of He II is captured here as well. World-famous physicists such as Lev Landau
Richard Feynman Peter Kapitza and Kurt Mendelssohn are key players in the story while secret
police from two different countries have a walk-on role. This work is meant for the general
reader. Without assuming any expertise in physics engineering or mathematics it illuminates
for the general public a little-known area of science and engineering and shows why it matters.
As it turns out it's also a good story.
