My new absolute favorite horror series is "The Monstrumologist" by Rick Yancey.  I picked up the first volume as a free "advanced reading copy" from a library convention several years ago, and donated it to the school library. 
Pretty rad cover image, right? Puts one in mind of a "Cabinet of Curiosities"
          I thoroughly enjoyed the first volume, but it wasn't until I read the sequel, The Curse of the Wendigo, that I decided, "Okay, this is TOTALLY my new favorite series."

My review of The Curse of the Wendigo for Goodreads & Shelfari:

Even though I read very little YA lit, I read the first book in this series and totally loved it. This sequel just gets bigger and better, developing more of the complex themes and compounding the tragedy and poignancy. The writing is so poetic at times, subtle and artful. Weirdly enough, it's also some of the most gruesome and shockingly brutal horror I've read in a long time. "The Curse of the Wendigo" is about the Monstrumologist's search for a murderous creature with a penchant for removing its victims eyes and faces and doing "creative" things with them. Set in the late 1800s, the meat of the series is the incredibly complex relationship between the self-absorbed doctor ("Monstrumology," or the study of so-called monsters, being his specialty) and his 11-year-old charge Will Henry, whose father died while in the dangerous employ of the Monstrumologist. The doctor never officially adopts Will Henry, yet they have a powerful and multi-layered bond. The story is told from Will Henry's point of view, from journals found after his death, and his tale is truly heart-breaking, as his beloved doctor drags him into situations no child should endure. In this book Will Henry is presented with a terrible decision in a life-defining moment. I was riveted. The time period provides for some awesome set pieces and descriptions, plus cameos by notorious real life characters such as Algernon Blackwood and Bram Stoker.

Scary red Wendigo face!!!
          I would like to also add that Will Henry's painful yearning for Dr. Warthrop's love really pulls the reader in. Dr. Warthrop is so cold and analytical and demanding of poor Will Henry that when the doctor DOES finally show some glimpse of affection, it's practically heart-rending. Very effective, from a writerly standpoint. I catch myself making all sorts of embarrassing facial expressions when reading these books, gasping and blurting out, "Oh, no!" or, "Don't leave the baby in that creepy hallway!"
          You better hope you don't hear the Wendigo's voice calling your name on the high lonely wind...