user12676: Does anyone know of a good (or not so) repertoire book on the Spanish with 5.d3 vs the main line and 4.d3 vs the Berlin? Is there such a thing on the market? I've already got Andrew Martin's DVD The ABC of the Ruy Lopez, but still I'd like to have something to read on the subject, something that would be a bit more thorough, etc.

user4588: There is a video series and e-book by GM Svidler on the Ruy Lopez with 6.d3. Although he considers the move order 5.0-0 Be7 6.d3, his analysis is probably also useful for you, as after 5.d3 Be7, the most popular and logical move is 6.0-0.

user924: The Ruy Lopez: Move by Move by Neil McDonald contains both a d3- and a main line repertoire against the Ruy Lopez.

12676: <p>Does anyone know of a good (or not so) repertoire book on the Spanish with 5.d3 vs the main line and 4.d3 vs the Berlin? Is there such a thing on the market? I've already got Andrew Martin's DVD The ABC of the Ruy Lopez, but still I'd like to have something to read on the subject, something that would be a bit more thorough, etc.</p>
 4588: <p>There is a <a href="https://chess24.com/en/learn/advanced/video/the-6-d3-spanish-according-to-svidler/introduction-to-the-6-d3-spanish" rel="nofollow noreferrer">video series</a> and <a href="https://chess24.com/en/learn/advanced/ebook/the-6-d3-spanish-according-to-svidler" rel="nofollow noreferrer">e-book</a> by GM Svidler on the Ruy Lopez with 6.d3. Although he considers the move order 5.0-0 Be7 6.d3, his analysis is probably also useful for you, as after 5.d3 Be7, the most popular and logical move is 6.0-0.</p>
 924: <p><a href="https://www.everymanchess.com/the-ruy-lopez-move-by-move" rel="nofollow noreferrer">The Ruy Lopez: Move by Move</a> by Neil McDonald contains both a d3- and a main line repertoire against the Ruy Lopez.</p>
