The world’s cities face increasing threats from natural disasters, aging infrastructure, traffic, and resource constraints. The articles in this issue examine smart infrastructure, sustainability, net zero carbon options, and autonomous driving, among other approaches to smart and sustainable cities.

• A Word from the NAE Chair: Infrastructure Here and Abroad
• Guest Editor's Note: Engineering for Sustainable Smart Cities
• A Metastructure Approach to Smart and Sustainable Cities

The covid-19 pandemic suddenly directed awareness to potential health impacts of the built environment of everyday living – schools, dwellings, offices, public buildings, and other spaces. This issue explores the “microbiome” of the built environment in the postpandemic reality in terms of ventilation performance, filtration, understanding and quantification of transmission risk, protection of “benign” microbes, and the important role of equity, among others.

• A Word from the NAE Chair: Engineering Leadership
• Editor's Note: Thoughts on the Future of the Building Microbiome
• Issue Editors' Note: Microbial Challenges in the Built Environment

The articles in this issue describe the latest technologies for detection of breast and other cancers, approaches to reduce the incidence of premature births, and remote monitoring for pregnancy, a development of particular interest as the pandemic discouraged many people from going to a doctor’s office or hospital.

• Editor's Note A Bridge to Public Engagement
• A Word from the NAE Chair: Implementing the NAE Strategic Plan
• Guest Editor's Note Enhancing Engineering Approaches to Understand and Treat Women's Health