In the fall of 1938, John Steinbeck and his wife, Carol, moved to the Santa Cruz Mountains. They had been living in Los Gatos (now Monte Sereno) off of Highway 9 (now Saratoga-Sunnyvale Road) on Greenwood Lane. Steinbeck said in a letter to a friend, "At the Greenwood Road place we were finally surrounded with little houses and right under my workroom window a house was built by a lady who was studying singing-- the mi-mi-mi kind so we finally went nuts."  They went in search of a place with more privacy. With the help of Carol's Father, they found a little ranch off of the Santa Cruz Highway just below Redwood Estates. It was a forty seven acre estate with a large spring. They moved into the old ranch house and began construction on their new home.

The Biddle Ranch, as it was known, had been settled in 1847 and the old ranch house was built shortly afterwards. John and Carol began construction on their new home in September of 1938, with completion in December. Steinbeck wrote to his friend Carlton Sheffield, "We came up, built a four room house for ourselves, much like the Greenwood Road house. There had been an oil well on the place and we used the big timbers and boards for our house."  Steinbeck loved his mountain hideaway so much so that he called it an estate. "Then since Carol loves to swim I asked about swimming pools and I discovered a curious thing. The cost of swimming pools isn't the pool but the machinery for filtering the water over and over since water is expensive. But we had a four inch head of spring water. Now we built a long narrow swimming pool and turned our spring into it. If it were a city pool with the big pumps and filters, it would have cost between eight and ten thousand dollars. But a concrete tank with a spring running in costs $1500."

John had begun writing The Grapes of Wrath in Los Gatos, but wrote the bulk of it on the mountain. It has been felt by his biographers that he needed the seclusion of his forty seven acre mountain retreat at that time in his career in order to be able to give his full attention to his greatest masterpiece. In a letter to his publisher on September 10, 1938, he stated, "The foundations of the new house are going in. Carol is typing the second draft"..."I am fairly sure that another sixty days will see it done."  On December first, Steinbeck sent the manuscript of the Grapes of Wrath to his publisher.

They moved into the new house and remodeled the old ranch house into "two guest rooms and a big winter playroom where they could have parties."  Steinbeck liked to entertain and had many friends who liked to come stay. "Charlie Chaplin professed to envy Steinbeck's country life and visited him several times." Carlton Sheffield who himself was a frequent guest, states in his book, The Good Companion, "Charlie Chaplin on his first visit described it as a 'forest by Adrian', who was one of the leading Hollywood set designers. And at a time when Chaplin was having domestic troubles, John quoted him as saying, 'When I get this picture opened and all the formal things done, can I please go up to your ranch and kick all the servants out and just talk a little bit quietly about how lonely and sad I am."   Sheiffield confesses that "there was always something new and diverting, and conversation never flagged, though often, after much wine drinking, the rough, twisting, exit road proved a bit hazardous".

Response to The Grapes of Wrath was widespead. It focused nationwide attention to the deplorable living conditions and the exploitation of the farmworkers from the dustbowl. Steinbeck wrote in a letter to a friend, "The vilification of me out here from the large landowners and bankers is pretty bad. The latest is a rumor started by them that the Okies hate me for lying about them. So I'm frightened at the rolling might of this thing. It is completely out of hand. I mean a kind of hysteria about the book is growing that is not healthy."

On the mountain, Steinbeck was able to retreat from the critical eye of the public. On February 27, 1939 he wrote in a letter to his publisher's assistant and close friend, Elizabeth Otis, "The ranch is beautiful now with spring coming. The fruit trees are just breaking into bossom. And the grass is deep and lush. It is very fine." Again on May 30, 1939, he wrote; "It is really warm--even hot now. I think I'll go and jump in the lake and cool off. I don't wear any clothes but a g-string anymore, not even shoes. The Filipino boy swears he saw a rattlesnake this morning but I don't believe him. There aren't supposed to be any on this side of the canyon."

Steinbeck was deluged with letters, telegrams and telephone calls when The Grapes of Wrath was published and he was elected to the Institute of Arts and Letters. Controversy over The Grapes of Wrath continued and the pressure became more and more intense. During this time, his marriage to his childhood sweetheart began to unravel. "Something has to be worked out or I am finished writing. I went south to work and I came back to find Carol just about hysterical. She had just been pushed beyond endurance... I thought this thing would die down but it is only getting worse day by day."

In June of 1939, the film rights to Of Mice and Men and The Grapes of Wrath were sold, so John started writing both screenplays. Under a lot of pressure, he escaped to the mountain where he wrote in October of 1939, "It's a beautiful morning and I am just sitting in it and enjoying it. Everything is ripe now apples, pears, grapes, walnuts. Carol has made pickle, and chutney, canned tomatoes. Prunes and raisins are on the drying trays. The cellar smells of apples and wine. The madrone berries are ripe and every bird in the country is here-slightly tipsy and very noisy. The frogs are singing about a rain coming but they can be wrong. It's nice." The films Of Mice and Men and The Grapes of Wrath were released as Steinbeck was preparing to leave for Baja California with his close friend, Ed Ricketts. In March of 1940, they departed aboard the Western Flyer for an exploration to collect and preserve marine specimens. His notes resulted
in the book, The Sea of Cortez. While he and Carol were in Mexico, The Forgotten Village was filmed there. That Spring he won the Pulitzer Prize in Fiction for The Grapes of Wrath. Soon after, concerned about the expanding war in Europe, Steinbeck returned to the mountain and began a period of loneliness and disenchantment with life. His marriage continued to dissolve when in Hollywood he met a young singer named Gwendolyn Conger. He fell helplessly in love. He was able to keep his secret from Carol for a time, but there estrangement grew.

He purchased a small house in Pacific Grove on Eardley Street in April of 1941 in order to work on the Sea of Cortez. The house was not far from Ed Ricketts' lab. For a time, he commuted on weekends to the ranch. Upon Carol's return from Hawaii, he informed her of his feelings for Gwen and they separated. The ranch stood empty for a time before being sold in August of 1941.