I've been to Cuba seven times. I met my wife on the second trip. 99% of tourists never leave the resorts, except for an excursion to Habana Viejo (Havana's old city). Most of the guidebooks are for those people, presenting only the places that tourists go. Of those guidebooks the Lonely Planet guidebook (Sainsbury, 4th ed.) is the best.
Only one guidebook covers every pueblito on the island. My 4th edition of the Christopher Baker's Moon Handbook is falling apart from too much use. I'm ordering the 5th edition for my trip in a few weeks. The Moon guide is not only complete, it is a pleasure to read. Baker is a fine writer. The photos and maps are excellent too. The history of Cuba in the back is better than some of the history books I've read. If you want to go to Cuba's less popular national parks (i.e., not Vinales or Topos de Collantes) you'll have to get Baker's guidebook, as this is the only book that covers the undeveloped national parks.
I liked Baker's guidebook so much that I read "Mi Moto Fidel," his book about writing the first edition of the Moon guidebook. My only complaint about the Moon guidebook is that it makes me want to take six months and see all the amazing places he describes. Also, my wife and Cuban in-laws are continually shocked at the out of the way places I want to see. They just want to go to a resort and lie by the pool (they weren't allowed to enter resorts until a couple years ago, so this is a dream to them). I want to go see something the Baker found -- an American fighter-bomber that was shot down in the Bay of Pigs invasion, miles down a rugged trail; or hire an ornithologist to go into a swamp to see a bee hummingbird (the world's smallest bird); or hire a guide to explore the Gran Caverna de San Tomas, Cuba's biggest cave.
**update** The 5th edition (2010) is much smaller. My favorite resort, Hanabanilla near Manicaragua, was left out because few tourists go there (which is one reason I like it). I wish that Christopher Baker had updated the 4th edition and then the publisher had released it on the Kindle. The 4th edition was heavy to carry around. What would be perfect would be to carry the Lonely Planet guide (in print) and have the 4th edition Moon guide on your Kindle.