I. Introduction  
II. Timeliness in Gossip Networks  
III. Age of Gossip  
IV. Age Scaling for Simple Network Topologies  
V. Age Upper Bound for Complex Networks  
VI. Clustered Networks  
VII. Age-Aware Gossiping  
VIII. Higher Order Moments of the Age Process  
IX. Sparse Networks  
X. File Slicing and Network Coding  
XI. Reliable and Unreliable Sources  
XII. Information Mutation  
XIII. Adversarial Actions in Gossiping  
XIV. Non-Poisson Updating  
XV. Gossiping with an Energy Harvesting Sensor  
XVI. Open Problems: Future Directions  
XVII. Conclusion