We thank the following reviewers for their contribution and support in 2021.

Piero Amodio

Italy

John J. Araujo

Colombia

Muthuswamy Balasubramanyam

India

Andre Gustavo Bonavita

Brazil

Yulong Cao

China

Bohao Chen

United States

Yu Chen

China

Tatvam T Choksi

United States

İlgun Özen Çınar

Turkey

Mario Coccia

Italy

Talha Bin Emran

Bangladesh

Ahmet Eroglu

Turkey

Kevin Escandón-Vargas

Colombia

Yu-Chen Fan

China

Isidre Ferrer

Spain

Xue-Qin Gao

United States

Qian Guan

China

Cheng Guo

China

Surampalli Gurunath

India

Tianzhen He

China

Jing He

China

Zhen-peng Huang

China

Li Jiao

United States

Mahmoud Kandeel

Egypt

Aynur Karadag

Turkey

Tom C Karagiannis

Australia

Majid Kazemtash

Germany

Nicholas Kipshidze

United States

Shardul D. Kulkarni

United States

Xinxing Lai

China

Adrienne Lam

Australia

Shijie Li

China

Xin Li

China

Huili Li

China

Xiaoyan Liao

United States

Michael Liebman

United States

Zhi-Hua Liu

China

Bin Liu

China

Chen Liu

China

Irene Maier

United States

Nobuyuki Murakami

Japan

Harishankar Ramachandran Nair

India

Pedro Henrique Narciso

Brazil

Nenad Naumovski

Australia

Chunlin Ou

China

Georgios Pampalakis

Greece

Lei Pei

China

Abdul Rehman Phull

Korea

P V Ravindra

India

Maria C. Sacchi

Italy

Francesco Salvatore

Italy

Celestino Sardu

Italy

Sage N Saxton

United States

Anand Singh

United States

Guangtai Song

China

Chunjuan Song

United States

Magdalena Stania

Poland

Katarzyna Tomaszek

Poland

Matevž Tomaževič

Slovenia

Xiang Wang

China

Ran Wang

China

Guiqi Wang

China

Haichuan Wang

China

Jin Wang

China

Karol Wróblewski

Poland

Dongze Wu

China

Bing Yang

China

Jianshe Yang

China

WanJu Yang

China

Lin Yang

China

Zhiping Yang

China

Sandeep Yerra

United States

Cheng Yuan

China

Fenglai Yuan

China

Wei-Lin Zhang

China

Sarah Zhang

China

Wei Zhao

China

Li Zheng

China

Jian-Hong Zhong

China

Igor A Zolotukhin

Russia