This is the eighth 'Three Investigators' mystery that Dennis Lynds wrote under his William Arden pseudonym and I'd argue that it's the best of them. It takes a similarly loving look at the Spanish heritage of California to his first effort, 'The Mystery of the Moaning Cave', and it does so with an admirable focus on research that surpasses that of 'The Secret of Phantom Lake'. It doesn't skimp on action and mystery, embracing paperwork but not losing itself in it, and it displays a real heart, something that rings out all the more given what we're hearing from Elizabeth Arthur of late, the daughter of series creator Robert Arthur who's currently continuing the series in the modern day.

In particular, racism is given a stark focus in the opening chapter. The boys start out at school, not a location I remember seeing in earlier books, where a fellow student wants to talk to Jupe. He's Diego Alvaro, a quiet but proud Mexican who knows him from the school's California History Club. Before he can explain what he wants, Skinny Norris, the one character we've always loved to hate in this series, outs himself as a racist, suggesting that Diego's family and every other wetback go back to Mexico where they belong. Diego slaps him, prompting a fight that ends when he saves his opponent from being inadvertently hit by a car. That prompts Skinny to muster a sort of apology, but he continues to be not just an annoyance but an actual villain this time out.

It seems that Diego and his older brother Pico are trying to live up to their heritage as one of the oldest families in the Golden State. Their land was given to them in a Spanish land grant in 1784, after Carlos Alvaro fought alongside Hernando Cortés to defeat the Aztec Empire and Lt. Rodrigo Alvaro accompanied Gaspar de Portolá's expedition north to San Francisco. They were awarded a generous five square leagues, over twenty-two thousand acres, but it's been whittled down over the centuries to a mere hundred acres. And now Skinny's father wants that too to expand his own neighbouring ranch.

In order to keep their land, they want to sell a bunch of stuff the family has collected over decades and Uncle Titus is eager to take a look at it. Unfortunately, just as he agrees to buy everything he can see in their barn, a brush fire kicks in between the Alvaro and Norris ranches and everything's dropped to take care of that. When long overdue rain finally puts it out and they head back to the Alvaro Hacienda, they find that both the house and the barn have gone up in flames too. Nothing survives. It's a cruel blow to a family already on the verge of disaster.

However, the boys encountered a single ray of hope in between the two fires, at the titular horse. The headless horse is a statue of Cortés on Alvaro land and the fire cylinder that decapitated it is a godsend, because it reveals what must be the scabbard to a jewel-encrusted sword Cortés gave to Carlos Alvaro a couple of centuries earlier. That sword disappeared in 1846 without a trace, but now the Three Investigators have a clue. It's not much of one but it's a clue nonetheless and they dive into the mystery for its own sake and for that of their new friends, more in need than ever.

It's a good mystery. I did catch the moment where Lynds set up part of the solution but hadn't got the entire picture figured out by the time Jupe reveals it. It's a neat deduction that brings it all to a conclusion, building strongly on the research the boys do earlier in the book but with need for a further leap. It's a strong conclusion, bolstered by the fact that Skinny is promptly sent off after it to a military school. I wonder if that moment of long overdue karma will remove him from the rest of the series or whether he'll be back on a break.

While the research quickly goes beyond the frustrating trope of Bob's dad dropping a key nugget of knowledge at a crucial moment to some real legwork in the newspaper archives, it doesn't stop there. To find the truth, the boys don't just have to work through old newspapers but diaries and army reports, even consulting the earliest maps available on the area, one of which they're forced to examine through protective glass. Lynds clearly loved history and that shines through what he puts the boys through here. Prof. Marcus Moriarty helps and I presume the unnamed help at the Historical Society is Stebbins from 'The Secret of Phantom Lake'.

The ironic catch, given that the key to this mystery is that what's generally accepted as historical fact is still open to correction, is that Hernando Cortés is seen as a hero, specifically by the Alvaros but also in a general sense. That hasn't aged well, even though this novel isn't particular old, only a breath under half a century. We know a lot more about Cortés now than we did and his brutality is likely more remembered today than his reign as the first governor of New Spain. To be fair, the author does raise many things that are topical today, not just racism, colonialism and awareness of Native American concerns but also nature and drought.

What that means is that 'The Mystery of the Headless Horse' would have been seen as much more progressive in 1977 when it was first published than today. However, in my opinion, it easily stands tall as the best of the William Arden contributions thus far. However, it's his last of two in a row so M. V. Carey is back next month with 'The Mystery of the Magic Circle'. ~~ Hal C F Astell

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