One area that makes a lot of sense (and not just to us- thanks for the comment, Carolyn!) is to pick up the books that are staples of a cruising boat's bookshelf. It’s possible some will come with the boat you purchase, but there’s likely to be minimal overlap. They can get very expensive if you pay full retail at the last minute. And besides, sinking into the pleasure of reading books that are part of your pending adventures can help keep you motivated and focused on reaching the goal of actually leaving and going cruising.
We put these into three general categories: references, regional guides, and local literature.

I think I'd actually wait to get this book. Taken on "cut the lines" day in 2008.
Essential References
A general cruising guide. There are a number of solid cruising guides available, and they generally come down to different points of view on how to do the same thing. The different philosophies or approaches to cruising will make one resonate for you. My pick is Voyager’s Handbook by Beth Leonard. It is comprehensive, clearly written, well organized, and thinks through topics from several angles or budget levels. If you're not sure, the library is a great way to try a few out.
Nautical references. Two which we think are imperative, but which in all honesty are rarely cracked, are Chapman's and Bowditch. These aren't just books, they're institutions! When you really need them, there's not a substitute...and they get expensive at retail.
Medical references. There are a lot to choose from. Like cruising guides, pick those that work best for you. We acquired ours during our advanced first aid course, which gave us the advantage of familiarity with them from the training.
Mechanical references. Two words to cover this: Nigel Calder! We swear by his Boatowner's Mechanical and Electrical Manual. Not realizing we had a copy, a commercial fisherman friend gave us another as a departure gift. Tells you something, right?
“Nice to Have” References
World cruising overview. I really like having Jimmy Cornell’s 2-book set, covering major seasonal cruising routes and country basics, as a handy reference. Reading through these helped think about top level route planning and the basics of what to expect in countries along the way.
Knots and splicing guide. If you’re into knots and splicing at any level beyond the basics, The Ashley Book of Knots is the one to have. Jamie learned from this as a teenager at the Mystic Seaport, and always wanted a copy. I’m not sure how but our crew to the Marquesas, Ty, also knew it was the perfect gift and hole on our bookshelf to fill.
Fishing guide. The Cruisers Guide to Fishing is full of practical information. My personal favourite: tips on filleting different species. We didn't catch the variety of pelagic fish we would have liked, but found a lot of helpful information here.
Selected cookbooks. We have a lot, because we love to cook, but I think most boats can use two: all-purpose cookbook (which you probably already have) and a cruising-specific cookbook. For covering the bases and including a lot of really great tips on provisioning, I really think Amanda Swan-Neal's The Essential Galley Companion is just that. Essential. For everything else, I love Mark Bittman's How To Cook Everything.
Regional guides
We did not anticipate how important regional guides would be, and departed with too few on board. Sure, we left with plenty books for Mexico, but that left us facing the difficult and expensive acquisition of books for the South Pacific after we had left easy access behind at home.
Regional cruising guides change infrequently, and can often be quite expensive. Find out which books you want for your anticipated cruising areas, and start trolling eBay for deals. For boats on the Pacific side of Mexico, Shawn and Heather's awesome cruising guides are excellent dream fodder, even if you won't need them for practical use for a couple of years. If you're planning to head across the Pacific, many of the Pacific Island guides can be hard to acquire. It can be really hard to visualize what you need.The year before we left, I couldn't have picked more than a couple of island nations out on a map, and that's probably being generous.
Country travel guides change a little more often, but the core content that I find most useful- historical overview, local maps, information on cultural norms- stay the same. Lonely Planet, Moon, Rough Guides... whatver you like: these are great to troll for 2nd hand from another traveler. Our guide to Fiji had years/miles but will still extremely useful.
Field guides to regional flora or fauna are even less prone to change. We get huge enjoyment from identifying what's around us and they can be hard (or expensive) to acquire after you depart. Bird guides, reef life and fish identification, plant life, marine mammals, etc. These are ideal to scope out at garage sales or thrift stores.
Local literature
It's hard to beat the incredible feeling of reading Melville's Typee when you're in the Marquesas, anchored at the very bay where he writes about being held as a captive in 1842. Reading literature tied to the areas you visit adds so much to what you can learn and enjoy about the places visited cruising. You appreciate culture in new ways, and see places you visit in new dimensions.
For a great list of titles for crossing the Pacific, our friends on Galactic wrote about their favorites. It seems we have a pretty good mind meld going there. Just read their list!
A note on digital
It should go without saying, but many of these are available digitally. Totem has been modified to add many (many) linear feet of bookshelves: we do love our books! Now that everyone aboard has a reader of some sort, I'll be happy to reclaim a few of those feet for other storage purposes. But... maybe this will someday seem old fashioned to the digital natives we're raising, but I find it hard to beat the hard copies for the majority of books listed here. I'm not going to be tucking my e-reader into a backpack to take into town, like I would with a travel or field guide. It's too flashy, and too subject to being broken / drowned / stolen. I'll keep my dog-eared paperback, thanks.
The biggest exception here are the local literature. These are books I'll be reading in the shade of the cockpit or on a soft evening at anchor. As much as I thought I'd mourn the tactile loss of a Book, it's not come to pass. One great advantage with many of the classic books is that they're available for free. It makes building this aspect of your library one of the really great areas you can put time and energy into before buying that boat, much less sailing off into the (low bandwidth) sunset.
Books: the first installment in useful cruising "stuff" I think you can reasonably acquire before you have a boat. The next installment... is percolating.
Essential References
A general cruising guide. There are a number of solid cruising guides available, and they generally come down to different points of view on how to do the same thing. The different philosophies or approaches to cruising will make one resonate for you. My pick is Voyager’s Handbook by Beth Leonard. It is comprehensive, clearly written, well organized, and thinks through topics from several angles or budget levels. If you're not sure, the library is a great way to try a few out.
Nautical references. Two which we think are imperative, but which in all honesty are rarely cracked, are Chapman's and Bowditch. These aren't just books, they're institutions! When you really need them, there's not a substitute...and they get expensive at retail.
Medical references. There are a lot to choose from. Like cruising guides, pick those that work best for you. We acquired ours during our advanced first aid course, which gave us the advantage of familiarity with them from the training.
Mechanical references. Two words to cover this: Nigel Calder! We swear by his Boatowner's Mechanical and Electrical Manual. Not realizing we had a copy, a commercial fisherman friend gave us another as a departure gift. Tells you something, right?
“Nice to Have” References
World cruising overview. I really like having Jimmy Cornell’s 2-book set, covering major seasonal cruising routes and country basics, as a handy reference. Reading through these helped think about top level route planning and the basics of what to expect in countries along the way.
Knots and splicing guide. If you’re into knots and splicing at any level beyond the basics, The Ashley Book of Knots is the one to have. Jamie learned from this as a teenager at the Mystic Seaport, and always wanted a copy. I’m not sure how but our crew to the Marquesas, Ty, also knew it was the perfect gift and hole on our bookshelf to fill.
Fishing guide. The Cruisers Guide to Fishing is full of practical information. My personal favourite: tips on filleting different species. We didn't catch the variety of pelagic fish we would have liked, but found a lot of helpful information here.
Selected cookbooks. We have a lot, because we love to cook, but I think most boats can use two: all-purpose cookbook (which you probably already have) and a cruising-specific cookbook. For covering the bases and including a lot of really great tips on provisioning, I really think Amanda Swan-Neal's The Essential Galley Companion is just that. Essential. For everything else, I love Mark Bittman's How To Cook Everything.
Regional guides
We did not anticipate how important regional guides would be, and departed with too few on board. Sure, we left with plenty books for Mexico, but that left us facing the difficult and expensive acquisition of books for the South Pacific after we had left easy access behind at home.
Regional cruising guides change infrequently, and can often be quite expensive. Find out which books you want for your anticipated cruising areas, and start trolling eBay for deals. For boats on the Pacific side of Mexico, Shawn and Heather's awesome cruising guides are excellent dream fodder, even if you won't need them for practical use for a couple of years. If you're planning to head across the Pacific, many of the Pacific Island guides can be hard to acquire. It can be really hard to visualize what you need.The year before we left, I couldn't have picked more than a couple of island nations out on a map, and that's probably being generous.
Country travel guides change a little more often, but the core content that I find most useful- historical overview, local maps, information on cultural norms- stay the same. Lonely Planet, Moon, Rough Guides... whatver you like: these are great to troll for 2nd hand from another traveler. Our guide to Fiji had years/miles but will still extremely useful.
Field guides to regional flora or fauna are even less prone to change. We get huge enjoyment from identifying what's around us and they can be hard (or expensive) to acquire after you depart. Bird guides, reef life and fish identification, plant life, marine mammals, etc. These are ideal to scope out at garage sales or thrift stores.
Local literature
It's hard to beat the incredible feeling of reading Melville's Typee when you're in the Marquesas, anchored at the very bay where he writes about being held as a captive in 1842. Reading literature tied to the areas you visit adds so much to what you can learn and enjoy about the places visited cruising. You appreciate culture in new ways, and see places you visit in new dimensions.
For a great list of titles for crossing the Pacific, our friends on Galactic wrote about their favorites. It seems we have a pretty good mind meld going there. Just read their list!
A note on digital
It should go without saying, but many of these are available digitally. Totem has been modified to add many (many) linear feet of bookshelves: we do love our books! Now that everyone aboard has a reader of some sort, I'll be happy to reclaim a few of those feet for other storage purposes. But... maybe this will someday seem old fashioned to the digital natives we're raising, but I find it hard to beat the hard copies for the majority of books listed here. I'm not going to be tucking my e-reader into a backpack to take into town, like I would with a travel or field guide. It's too flashy, and too subject to being broken / drowned / stolen. I'll keep my dog-eared paperback, thanks.
The biggest exception here are the local literature. These are books I'll be reading in the shade of the cockpit or on a soft evening at anchor. As much as I thought I'd mourn the tactile loss of a Book, it's not come to pass. One great advantage with many of the classic books is that they're available for free. It makes building this aspect of your library one of the really great areas you can put time and energy into before buying that boat, much less sailing off into the (low bandwidth) sunset.
Books: the first installment in useful cruising "stuff" I think you can reasonably acquire before you have a boat. The next installment... is percolating.