articles and knowledge

A 101-page journey back more than 500 million years to the Cambrian Explosion, when complex life burst onto the scene. Here's what's inside, who it's for, and where to read it on Google Play Books.

Four focused engineering guides from ChatVariety Team covering electric aircraft propulsion, urban air mobility, railway signaling and autonomous maritime systems — with a recommended reading order and Kindle and paperback links.

A review of Thai Language Practice M.1–3, a free iPhone and iPad app with 3,000 Thai questions for grades 7–9, step-by-step explanations, timed mock exams and a mistake notebook that works offline.

A close look at TOEIC Prep for Android: practice all 7 Listening and Reading parts, 430 original questions, step-by-step strategy lessons, 1,036 business words with audio, full mock tests with an estimated score, and offline study. Free on Google Play.

An engineering guide from the Advanced Mobility Engineering Series covering aviation battery systems, motor controllers and certification for electric and hybrid aircraft. On Kindle and in paperback.

A review of ChatStick's middle school science quiz app: 3,000 questions across M.1–M.3 (Grades 7–9), explanations for every answer, mock exams, a 100-question Grand Test and a mistakes notebook. Free on the App Store.

An 82-page guide to the leaders, battles, achievements and cultural legacy of ancient Persia's empires. Here's what's inside, who it's for, and where to read it on Google Play Books.

A practical paperback from the Smart Car Buying & Ownership Series that helps everyday drivers understand their car insurance coverage, handle claims and lower their premium.