This book is written with an intention to point out clear differences between the personality traits of only born adolescents and sibling adolescents. This would further help the readers to be bias free against either of the types of adolescents. The criteria of personality which are addressed, evaluated and interpreted are reservedness, intelligence, emotionality, excitement level, assertiveness, enthusiasm, conscience, adventure, tender mindedness, zest, apprehension, self-sufficiency, control and tension level. This book is based on a research conducted on a larger sample on the same topic. On careful reading and observation, each reader will be able to relate the topic to his personal life and developmental progress. Lastly, this book can prove to be beneficial for further research related to adolescence and personality.