It's difficult to determine the most popular arts and photography book since there are numerous books in this category that have achieved critical acclaim and widespread popularity. However, one book that stands out as a perennial favorite among readers and critics alike is "Ways of Seeing" by John Berger.

Published in 1972, "Ways of Seeing" is a collection of seven essays that explore the relationship between visual art, society, and culture. The book is divided into two parts: the first part consists of four essays that focus on how we see and interpret images, while the second part features three essays that examine specific works of art.

Berger's writing style is clear and accessible, making complex ideas and concepts easy to understand for readers of all backgrounds. He draws upon his experience as an art critic and novelist to offer insightful commentary on the social and political implications of visual art, challenging readers to think critically about the images they see and the ways in which they are constructed.

One of the key themes of "Ways of Seeing" is the idea that our perception of images is shaped by the social and cultural context in which we live. Berger argues that our understanding of art is not purely aesthetic but is heavily influenced by our cultural and historical background. He encourages readers to think beyond the surface-level beauty of an image and to consider its historical and social significance.

The book also includes a number of striking images, including works by artists such as Leonardo da Vinci, Rembrandt, and Picasso. These images are used to illustrate Berger's points and to demonstrate the ways in which visual art can be both a reflection of and a catalyst for social change.

Overall, "Ways of Seeing" is a thought-provoking and influential book that has had a lasting impact on the fields of art and visual culture. Its accessible style and broad appeal have helped to make it one of the most popular and widely-read arts and photography books of all time.