Series fiction

Star Trek: The Next Generation: Loyalties (1996)

Star Trek: Voyager: Quarantine (1997)

The Secret World of Alex Mack: Junkyard Jitters (1997)

The Secret World of Alex Mack: High Flyer (1997)

The Secret World of Alex Mack: Computer Crunch (1998)

Salem’s Tales: Teacher’s Pet (1999)

Sabrina, the Teenage Witch: Magic Handbook (1999)

Sabrina, the Teenage Witch: Guide to the Universe (2000)

Series non-fiction with co-author Thomas Svarney

The Handy Dinosaur Answer Book (2002)

The Handy Oceans Answer Book (2003)

The Handy Geology Answer Book (2004)

The Handy Math Answer Book (2006; rev. 2012)

The Handy Biology Answer Book (2014) 

The Handy Nutrition Answer Book (2015)

The Handy Anatomy Answer Book (2016)

The Handy Diabetes Answer Book (2017) 

The Handy Forensic Science Answer Book (2018) 

Single non-fiction books with co-author Thomas Svarney

Skies of Fury: Weather Weirdness Around the World (1999)

A Paranoid’s Ultimate Survival Guide (2002)

The Oryx Guide to Natural History: The Earth and All Its Inhabitants (1999)

Single non-fiction books 

The New York Public Library Science Desk Reference (editor/writer; 1995)

Asteroid: Earth Destroyer or New Frontier? (2004)

When the Earth Moves: Rogue Earthquakes, Tremors, and Aftershocks (2007)

Why Do Women Crave More Sex in the Summer: 112 Questions That Women Keep Asking—and That Keep Everyone Else Guessing (2012) 

Single books – middle reader and young adult

The National Science Foundation (series; 1989)

Zimbabwe(series; 1990; rev. 1997)

Fossils: Stories from Bones and Stones (1991)

Clocks in the Rocks (1991)

Born of Heat and Pressure: Mountains and Metamorphics Rocks (1991)

The Traveler’s Guide to the Solar System (1993)

Secrets of the Sun (2000)

A House for Wanda Wood Duck (2002)