The casual visitor to Palm Springs could be forgiven for regarding the city as architecturally undistinguished. But much of the beauty of its buildings reveals itself only when you have penetrated the outer walls. We therefore engaged the services of a guide. Michael Stern, co-author of “Julius Shulman: Palm Springs,” leads exclusive tours of the city’s Mid-Century Modern highlights, including the interiors of some private homes closed to the public. Tours can be customized, but we sought a general overview. Our itinerary included a visit to the angular William F. Cody-designed Horizon Hotel, where we viewed the striking Residence, the former home of film actress Bonita Granville. We also wandered through a middle-class Donald Wexler steel house. And Stern encouraged us to look at more familiar city landmarks, such as the visitors’ center and art museum, in a new light, pointing out elegant details we would otherwise have missed. Tours cost $150 per person, and we won’t hesitate to take another spin with the engaging Mr. Stern on our next visit to Palm Springs. The Modern Tour, Tel. (760) 904-0904.