The Globe Illustrated Shakespeare: The Complete Works is an annotated hardbound book that contains all works written by William Shakespeare. Jean-Luc Picard owned a copy of this book and kept it under a glass cover in his ready room.
According to Berlinghoff Rasmussen, historians from the 26th century believed the captain had kept his volume of the Complete Works on his desk and not under a glass cover on a small table. (TNG: "A Matter of Time")
This book was among the items Edward Jellico reminded Picard to remove from the ready room after Picard relinquished command of the USS Enterprise-D to Jellico in 2369. (TNG: "Chain of Command, Part I")
Background information Edit
The copy used on the set was the 1986 Greenwich House edition. Written and annotated by Howard Staunton (1810-1874), it was attractively bound but that version is generally looked upon by Shakespearean scholars today as being outdated in terms of its scholarship. For purposes of Trek we may be safe in assuming that Picard's version is an updated one or an antique.
Patrick Stewart who plays Captain Picard is a noted Shakespearean actor, and was in the Royal Shakespeare Company for a number of years. He made his broadway debut in Peter Brook's production of A Midsummer Night's Dream.