## 2022 BOOK [A Half-Century of Universal “Anomalies” of Glasses](https://www.worldscientific.com/worldscibooks/10.1142/q0371#t=toc)
## BOOK [Tunneling Systems in Amorphous and Crystalline Solids](https://books.google.ru/books?id=NMc3II1XICYC&pg=PA518&lpg=PA518&dq=leggett+universality+glasses&source=bl&ots=ZCR5k7LTxR&sig=ACfU3U0rusukbGmKdugjCIGjKG_uw8sLPA&hl=en&sa=X&ved=2ahUKEwiXq4Sl6IvzAhUilosKHQ62ANQQ6AF6BAgUEAM#v=onepage&q=leggett%20universality%20glasses&f=false)
By Pablo Esquinazi
## 2021 BOOK [Low-Energy Excitations in Disordered Solids : A Story of the 'Universal' Phenomena](https://www.worldscientific.com/doi/pdf/10.1142/9789811217258_0001) Richard B Stephens and Xiao Liu
https://blackwells.co.uk/bookshop/product/Low-Energy-Excitations-In-Disordered-Solids-A-Story-Of-The-Universal-Phenomena-Of-Structural-Tunneling-by-Richard-B-Stephens-Xiao-Liu/9789811217241
## Universal properties of glasses (at glass transition and low temperatures below 1K)
The universality is remarkable, but yet to be described beyond phenomenological standard model of tunneling two-level systems.
- [the problem articulated by Tony Leggett already in 1991!](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5373/Leggett%2B1991%2Bwhy%2Bsimilar.pdf)
