This Companions of the Prophet series by Abdul Wahid Hamid, published by MELS, is hands down THE BEST English language collection of Sahaba stories ever.
Beautifully written with vibrant, powerful energy, I can truly say that these books instilled in me a love of stories of the Sahabah from a young age. The author mentions not only the most famous Sahabah, but also the more obscure ones, whose stories are rarely mentioned in most English books.
This book is ideal for everyone from young adults to elders, and possibly even from middle grade onwards.
I cannot recommend this series enough - as a personal read, as ideal for reading aloud in youth groups/ halaqas, and as required reading for Islamic school classes.