Each year as I put together some suggestions for Christmas gifts and stocking stuffers, I look to see if there’s some underlying theme or idea. What seems to unite my choices this year is the glimpses that they offer into worlds that are hidden or largely unseen. And in doing so, each in its own way provides a revelatory window into the mysterious and grace-filled experience of being alive. This year I’ve been reading a lot of behind-the-scenes books about Broadway musicals. Ted Chapin’s “Everything Was Possible,” about his time as a college intern on Stephen Sondheim and Hal Prince’s “Follies,” is a tremendous work. So is Elysa Gardner’s “Magic To Do,” about the making of the Stephen Schwartz and Bob Fosse musical “Pippin.” For lovers of the Art Institute, home of Georges Seurat’s extraordinary “A Sunday on La Grande Jatte,” I highly recommend writer/director James Lapine’s “Putting it Together,” an oral history of the making of his and Sondheim’s musical “Sunday in the Park with George,” which is inspired by that work. While the finished musical would go on to win the Pulitzer Prize and is celebrated as one of Sondheim’s greatest works, behind the scenes it had its fair share of drama, with preview crowds walking out in the second act and Sondheim unable to produce some of the show’s key songs until days before it opened. What I most adore about the book, though, is the space that Lapine gives to his collaborators — the actors, the designers, the musicians. It’s a rare thing for a creator to share the stage in this way, and the result is as fulsome a look at the process involved in creating a show from first idea to final bow as one could ever hope to see.